“Back when I was a soldier on Kinmen, around 1975, the water demons still sometimes killed people,” Xu Shifu (Master Xu) said. The laugh-lines at the corners of his eyes were not visible now, even in the white fluorescent light shining down from the ceiling. “When it was my turn for guard duty at night and everyone else went down into the bunkers, I was scared. I would turn my cap backwards . . . I knew the water demons would approach from behind. But in the darkness, all they could see was a person’s silhouette. I thought that would fool them into coming at me head on.”

Without his smile, Xu was as I had first seen him in Sun Yat-sen Memorial Park in Taipei, wearing the same white T-shirt and black pants as his students but standing a little apart from them. A trim, erect, gray-haired figure, he wore a traditional Chinese kungfu teacher’s expression, stern and observant. He was, in fact, a comedian, who regularly interrupted his own explanations of tai chi moves to tease his students until they convulsed with laughter.

Wonderful, one of Xu’s students, had arranged our meeting in Keelung, a port city northeast of Taipei where Xu and his wife Shimu (our “teacher-mother”) lived. Wonderful—his real name was Huang Defu, but the English nickname had stuck—was a fit and cheerful man in his early 50s. He now sat next to Xu, drinking a cup of apple vinegar and translating for me whenever Xu veered into Taiwanese. (The dialect, like the families of most Taiwanese themselves, had emigrated hundreds of years ago mainly from China’s Fujian province, and is now filled with expressions unique to Formosa.) Wonderful had served as a soldier on Kinmen in 1985, a decade after Xu. The two of them were among the ten million Taiwanese men who have been sent to guard the island since 1949. In that year, after losing the Chinese Civil War, Chiang Kai-shek and the Nationalists had retreated from mainland China to Taiwan, but had managed to keep hold of Kinmen, Matsu, and Penghu—the “coastal islands” which lay between them.

At only 1.2 miles from the Fujian coast, Kinmen was the main theater of a war between the two Chinas: the People’s Republic of China led by Chairman Mao, and the Republic of China led by President Chiang. In October 1949, at Guningtou on the northwest tip of Greater Kinmen, the main island, their armies waged a fierce battle. At least 5,200 young men on both sides lost their lives. The battle marked Kinmen’s separation from the mainland regime. It was a tiny piece of land—its two main islands are roughly 70 square miles, and today are home only to about 130,000 people—but Kinmen would loom huge in the geography of Cold War Asia. (The United States, which knew Kinmen by its name in the local dialect, Quemoy, sent advisors there.) For decades, missiles and propaganda balloons traveled back and forth. And there were the “water demons”—the shuigui, or frogman teams, that swam between Kinmen and the Fujianese city of Xiamen at night.

Sim Chi Yin—VII Photo for ChinaFile A statue of a soldier faces the waters beyond Lieyu Island, also known as Little Kinmen, a tourist stop for visitors interested in the military history of the region.

“By 1975, the water demons were tired of killing,” Xu told me. “Most of them just fulfilled their duty by taking something, some object or personal possession, as ‘proof’ for their superiors. Their superiors were tired of it, too.” Perhaps the frogmen would take a packet of cigarettes, or a weapon, or a scrap of paper they could call intelligence. The corners of Xu’s mouth were suddenly twitching: the comedian had returned. “In the early days, Anna, the shuigui would cut off an ear or a—”

He was interrupted by squirms and gasps from the others, including his wife. “Why speak of things like that, she doesn’t want to hear them!” she scolded him.

“Both sides used special loudspeakers.” Wonderful stepped in. “They had a longer range than most.”

“What did mainland China say through their loudspeakers?” I asked.

Wonderful, beaming, drew himself up stiffly and expanded his chest. “Dear Taiwanese compatriots!” he boomed, raising one hand to the side of his mouth to amplify the sound. “Hurry and return to the embrace of the Motherland!”

“That’s the same thing they said when I was there,” Xu observed.

“They would describe how good it was over on the mainland,” Wonderful added.

“And what did you say to them?”

“In the evenings, we’d play them songs,” Wonderful said. “We liked to use music to touch their hearts. We played Deng Lijun. Do you know Deng Lijun?”

“You ask how deeply I love you. . .” I crooned, doing my best imitation of Taiwan’s iconic songbird. “The moon represents my heart.”

“Yes! Deng Lijun!” Wonderful smiled. “We said it was our ‘Little Deng’ versus their ‘Old Deng,’ Deng Xiaoping.”

* * *

In the summer of 2014, around the same time Xu was telling me about the water demons, hundreds of swimmers took off from the coast of Fujian province, in China, and headed toward Kinmen. They were mainland Chinese and Taiwanese, battling, now, to win the sixth jointly sponsored Xiamen-Kinmen Cross-Strait Swimming Race. The annual race is one of dozens of new joint cultural, academic, and trade activities now linking the mainland to Taiwan’s outpost. There are physical links as well. Giant underwater pipes are expected to start delivering water from Longhu Reservoir in Fujian province to Kinmen by the end of 2017. (Within a decade, they will provide 40 percent of the island’s water.) Sketches for a “peace bridge” between Kinmen and Xiamen have been created, and a mainland billionaire has offered to fund it. The bridge remains just a plan. Still, Kinmen has transformed: Once a bulwark against the mainland, it is now a laboratory for experiments in a closer Cross-Straits relationship.

Photo Gallery A Cold War Island Thaws Sim Chi Yin Mounds of sand sit beneath a row of pile drivers on Dadeng Island, where the Chinese city of Xiamen is building a new airport on reclaimed land.Syril Hung sighs, awe-struck by this scene. The retired editor is looking through a pair of binoculars...

This change in Kinmen’s status became possible when the People’s Republic of China, newly recognized by the United States and most other nations, initiated its “Reform and Opening” under Deng Xiaoping. In the late 1970s and 1980s, Deng had decided that China was going to join the global economy, and Taiwanese were welcomed to the mainland as Chinese-speakers with business acumen and money to invest. In 2001, to accommodate the increasing flow of people across the Taiwan Strait, the two sides initiated the first major experiment on Kinmen, along with Taiwan’s other coastal islands: direct post, transportation, and trade links to mainland China. The “Mini-Three-Links” experiment was a success, and the links were extended from Kinmen another hundred miles to the island of Taiwan. Kinmen is, in some ways, a good testing-ground. It has deeper historical ties to China than Taiwan proper, and has never stopped communicating with it. Even in the mid-1970s when tensions were high between the two sides, a few Kinmen locals have told me they continued the ancient habit of rowing small fishing boats over to the city of Xiamen for a meal and a change of scenery. No one could tell they were not locals.

Shimu, Xu’s wife, whose family was from Kinmen, told me that reunification was inevitable and natural. She told me that Taiwan and China were like an estranged married couple. “They may quarrel a lot,” she had said, “but what outsider can truly understand what goes on between them?”

I decided to try, and Kinmen—the first break and the first link between China and Taiwan—seemed like a good place to start. In January 2015, I boarded a plane from Taipei to Kinmen.

* * *

Sim Chi Yin—VII Photo for ChinaFile A miniature, battery-operated Dassault Mirage 2000 fighter jet—a scale model of the ones the Taiwan Air Force uses—zooms past an open field in Kinmen.

In Kinmen, the sun is bright and the sky is blue. I am staying in a refurbished Fujianese-style courtyard house, one of many minsu, or family-run hotels, in the small neighborhood of Shuitou. It is a lovely place, but walking along the streets one discovers something odd and heavy in the silence. It is the kind of emptiness you might find in a tomb. Even under the noon sun, there is an eerie and penetrating silence. I pass small abandoned houses, their windows dark, doorless doorways into their courtyards showing forests of weeds and litter grown up over the flagstones. “The families left,” I am told by a local whose relatives have departed for Malaysia. “Life on Kinmen was bitter for a long time.” She is talking about the war between the Communists and Nationalists, but also of what came before: Japanese occupation during World War Two, and before that pirate attacks and general difficulty making money from the wind-stripped soil. Generations of huaqiao, or overseas Chinese, left Kinmen for Southeast Asia. Many never returned. At night, the wind—the loudest sound on the island—moans, barrels across the empty fields and streets; it grabs the old wooden doors of the houses and shakes them. In those moments, it is easy to believe in the ghost stories told by locals and soldiers, of spirits of those killed in wartime, who still cannot find rest.

On my second full day in Kinmen, I go to see Mr. Weng Mingzhi, the chief organizer for Taiwan’s Democratic Progressive Party on the island. He is standing in his front garden in muddy boots, looking happy. The air is fresh, the sky clear. Inside, over garlic-and-sugar-seasoned rice puffs, he acknowledges the difficulties of his work on Kinmen; the locals, he says, are “conservative” and “suspicious.” They vote overwhelmingly for the Nationalist Party, or Kuomintang (KMT). For many decades, the KMT was the state and the state provided the island with everything. The KMT once called itself the rightful representative of China. Today it is the party that emphasizes the importance of strong Cross-Straits ties. The Democratic Progressive Party (DPP), Taiwan’s first and main opposition party, was born in 1986 on the eve of democratization. It is part of the “green” coalition of political parties, and has a history of pushing for Taiwanese independence, which voters still associate with it today. Its focus, as such, is more on the tobacco-leaf-shaped island of Taiwan itself. Kinmenese doubt that the DPP considers their own little island an essential part of Taiwan, worth risking soldiers’ lives for. But things are changing. The island’s long-serving KMT magistrate, Li Woshi, has just been voted out. The new magistrate, Chen Fuhai, a member of the People First Party, is still part of the “blue” camp, along with the KMT. But Weng is optimistic. The number of DPP voters here, he says, is growing. (A year from now, though neither of us know it at the time, the country’s “green” forces will propel the DPP to a decisive presidential victory and to control of the national legislature. The KMT would win Kinmen in these elections, too.)

He is not worried about mainland influence on Taiwanese politics. This is surprising: in Taiwan proper, there is much concern about pro-mainland Taiwanese businesspeople buying up influential media outlets and otherwise using their money to press the reunification cause. But Weng says that the businesspeople, too, are now voting for the Democratic Progressive Party in large numbers. “I think they have woken up,” he says. “They realize that the reason they get so many perks from the mainland is because, at present, they are like a woman being courted.” The KMT seems willing to reunify with mainland China, he notes, to let it happen gradually, economy first. The hard-to-get attitude of the DPP “is like a smart woman who doesn’t give in right away when she’s being courted; first, she says, ‘Buy me a house, or a car.’” He smiles brightly and expands the metaphor: “That way, if reunification happens, at least we can get a better deal, like a woman getting a better marriage offer. No, the DPP doesn’t necessarily oppose reunification. We’re the Democratic Progressive Party; if the people decide on reunification, that’s fine as long as it’s their choice.”

For the fate of someone who has not played it smart, the people of Kinmen and Taiwan do not have to look far. “Just how much special treatment does Hong Kong get now, now that it’s back together with the mainland?” Weng asks rhetorically. The mainland had promised Hong Kong all sorts of things before they reunited. “Fifty years the same,” he reminds me, is what they were told; look at what they got.

Sim Chi Yin—VII Photo for ChinaFile Li Congli, originally from the mainland, sells fish at the busiest market in Kinmen, in Jincheng town. She is one of about 2,000 lupei, or mainland Chinese women, who have married Taiwanese men and moved to Kinmen. She asked a matchmaker to introduce her to her current husband, a worker in Kinmen’s famous sorghum liquor factory—the cash cow in the island’s economy.

Marriage, I have learned since Shimu first used the metaphor, pops up often in Taiwanese descriptions of the Taiwan-China relationship. This reminds me of something, and I ask Weng to tell me more about the China Production Party. It is a Taiwanese political party founded by and comprised of lupei, the mainland wives of Taiwanese men, and its founder, Lu Yuexiang, had been in town a few months back to establish a party branch on Kinmen. “She has her own ideal of getting the two—the mainland and Taiwan—back together,” Weng says. “Look at the flag of the China Production Party, it has the five stars of the P.R.C. flag. ‘Production’ also has the meaning of producing babies, of course.”

Before the mainland and Taiwan opened up to each other, he explains, Kinmenese men, and Taiwanese men in general, were looking for producers of babies; they couldn’t depend solely on Taiwanese women, with their higher levels of education. First, the men found Filipina and Vietnamese wives, but it proved problematic. “They’d have to make hand gestures to understand each other!” Weng says. Now, there are the lupei. More Taiwanese men are marrying mainland women, especially on Kinmen, he says. “At least we speak the same language. And now that you can travel easily back and forth, people can get to know each other slowly. It’s more of a real love story now. . .”

I have read about the China Production Party in the Taiwanese media. The party has, indeed, chosen a flag with the five stars of the People’s Republic, printed on a blue background. Lu Yuexiang, a round-cheeked, pleasant-looking woman in her fifties, a Fujian native, recently took fellow party members to Beijing for what she called “cadre training.” She says that she reports to the P.R.C. State Council’s Taiwan Affairs Office each month. Her party does not yet compete successfully in elections, but as a growing block of voters they draw candidates to their door. Kinmen’s newly-elected magistrate and most senior official, Chen Fuhai, had reportedly extended his congratulations to them in person when the Kinmen office opened. The party members chose October 1 to hold the ceremony: China’s National Day.

I take a cab to the China Production Party’s Kinmen headquarters on a whim, and without an appointment. The modest storefront of the headquarters is shuttered. Employees of the real estate office next door explain that members come when they have time; they must be busy. Kinmen is a small place, though, and someone says they know a party member. Suddenly I am sitting in the front room of an auto repair shop nearby, and Yang Yuxia is serving me coffee. She is originally from Anhui province, but met her husband while selling clothes at a Taiwanese-owned shop in Xiamen. She is lovely, with glowing skin, swingy coppery-tinted hair, and a gentle voice. She tells me another member will be here very soon. Luo Jianhua arrives almost immediately afterward, two children trailing behind her. Her eyes are streaming from a nasty cold. She is from a village in the mountains of Guizhou, she tells me, after joining us on the couch. She spent much of her life caring for her bedridden father and didn’t marry until she was 35. “To be honest, when my father died, it was a kind of release,” she says. She looks a little troubled. “It’s very unfilial to think that, isn’t it?”

Both women were horrified when they first arrived on Kinmen. “It was so desolate,” Yang says.

“In school, our textbooks said, ‘Taiwan is our beautiful treasure island,’” Luo says.

“I thought the whole thing would be made of precious jewels!” Yang says, and laughs. “When we got here, I cried so hard my husband felt sorry for me. He said, ‘You can go back if you want!’”

Kinmen in 2000, the year the women married local men, was a more isolated place, and for lupei, it was lonely. Luo cared for her young children herself, unable to bring her mother across to help her. It was lonely, moreover, because of how Kinmenese saw them.

“There was a vegetable,” Luo says, and Yang begins to nod, vigorously. “There was a vegetable called dalu mei, ‘mainland little sister.’ That’s what they used to call us. It wasn’t a good thing,” she adds. “There was that—and they would overcharge us when we went to buy vegetables at the market.”

“My mother-in-law used to say, ‘No, don’t you go, it’s always more expensive when you do the shopping!’” Yang told me ruefully.

The two women’s lives, after the suffering of the early years after marriage, have finally improved. No one asks anymore whether they have seen a fridge or used a light bulb. “They were like frogs peering out of the bottom of a well,” says Yang. But Kinmen has changed—everything has changed, for the better.

I ask them why they joined the China Production Party, and they both say it is because of its founder, Lu Yuexiang. “I read about her online,” Yang says. “She has a loving, compassionate heart. She has helped homeless people, people who were out on the street, find work!”

The only evidence I later find of what she has mentioned is a description in an online article of Chairwoman Lu (as she’s called) receiving desperate mainland wives who have been kicked out by their husbands. The lupei must depend on their Taiwanese husbands to support them until they are permitted to work. In the beginning, the two women tell me, wives had to wait eight years. “So a woman might go to work illegally in a restaurant and the police would raid it, and she’d be arrested and put in jail,” says Luo. It also meant that women in abusive relationships were trapped.

Both Luo and Yang credit Lu Yuexiang and the China Production Party with improving the laws that apply to lupei. “She is a good person and our good example,” Yang says ardently, sitting up on the sofa.

I mention that I’ve read the party charter, which lists as its main goal “peaceful reunification.”

“No, no, you misunderstood,” insists Luo. “It is only peace across the Straits.”

“They’re trying to smear black on our faces,” Yang says unhappily.

“So one doesn’t have to desire reunification to be a party member?”

“No!” they answer in unison. (When I return to my hotel, I go back to the China Production Party’s official website and check its charter; “peaceful reunification” is there, as I remembered it, at the very top.)

“If the mainland moved for reunification,” says Luo, “we wouldn’t necessarily want to go back. The government here treats us well, but over there they might not.” A loud crash interrupts the conversation. “You guys can’t afford to pay for that!” Luo tells her children, who have tossed a ball into a glass cabinet while playing catch. Fortunately, it doesn’t break.

Yang says that she, too, wishes to “maintain the status quo.” It is easy to forget that she is from the mainland, for this is a phrase often repeated by Taiwanese, almost as a mantra with preventive powers. As for China, it is the place the women take their Taiwanese-citizenship children once a year, to see their grandparents. It is a good place to shop. It is a place, they say, that will be democratic someday, because that is “where the world is heading.” “But there are too many people there, and their quality is still too low,” Ms. Yang says. “It is better if it happens slowly.” Otherwise, she says, it could be chaotic—like Taiwan. She speaks with distaste of vote-buying and fisticuffs between legislators.

“I wouldn’t want the mainland to use force for reunification,” Luo says, “because then there’d be war.” I ask her what kind of place she hopes Kinmen will be 40 years from now. She says she hopes people, including her kids, can move at will between the san di, the “three locations” of the mainland, Hong Kong, and Taiwan. She says she wants them to move freely, to be treated equally, to live and earn money in any of those places. Her face looks bright as she describes this freedom of movement: no barriers, no prejudice of one kind of Chinese person against another.

As a parting gift, one of them offers me their Chairwoman’s card; it features a photograph of Lu Yuexiang shaking hands with Taiwanese then-President Ma Ying-jeou. “You just missed her! She’s over in Xiamen now,” says Yang. “She has her own shops. Next time you go over to Xiamen, you'll have a place to stay! She’ll take you around town for some fun!”

The next day, I ask a local cabdriver about the mainland little sister vegetable—a type of lettuce, I have discovered. He wrinkles his nose. “It was smuggled over, before trade with the mainland opened up. It was nice and tender, but it had a strong, fishy smell. We don’t have them here anymore; we Taiwanese bred a better version of it. It smells good.”

Mr. Chen, in his late forties, sports a chest-hugging black turtleneck and the gentle arrogance of the very conscientiously fit. (“I surf,” he explains. “You should work out, too.”) He shares the cab with his older brother. Kinmenese once made their money from generations of soldiers like Xu and Wonderful, who had little to do in their free time other than patronize the local businesses. But a closer relationship with the mainland means the Ah Bing Ge, as locals call them (the “G.I. Joes”), are a much rarer sight now, and Kinmenese have to look to new places for a living.

“I don’t like people in Xiamen very much, to be honest,” Chen says. “I don’t like all the skyscrapers, or the environment, and the people’s quality has still not risen.” He adds, frowning, that mainlanders are already using the method of buying houses on Kinmen to “occupy” the island. “They’re happy to buy property here,” he says. “They only get a 70-year lease over there, but here, they can purchase property by partnering with a local or a Taiwanese and forming a company. Then they can pass it on to their descendants. . . The Hong Kong people, when they visit us here, they curse the mainlanders every day.” The influx of mainlanders there has inflated prices beyond the reach of locals. It isn’t fair.

If you are Kinmenese, you love the place where you are and you do not want to put it in anyone’s hands but your own. It is this feeling, a connection to place and a way of life, that fuels resistance to reunification or “mainlandization”; even, it appears, among transplanted mainlanders like Luo and Yang. For some, certainly, democratic rights are the most important issue, but Weng, the Democratic Progressive Party organizer, has told me that it is practical unfairness, not democratic ideals, that will get Kinmen locals onto the streets to protest.

The balance on Kinmen, it seems, has not tipped to the point of protests. “I like to make money,” Chen says now, looking me in the eye in the rear-view mirror. “If I can earn money from them, I think I can tolerate it.” Later, when I ask about the air pollution that floats in from Xiamen, another local says mildly, “Yes, they do send over polluted air, but they will be sending over fresh water, too.”

* * *

Sim Chi Yin—VII Photo for ChinaFile A Chinese saying describes the relationship between Taiwan and China as, ‘as close as lips and teeth.’ But younger Taiwanese are increasingly uncomfortable with this formulation.

So far I have spoken mostly with the middle-aged and old on the island. They seem comfortable, like many of their counterparts on Taiwan, with ambiguity, with being neither officially independent nor reunified with the mainland; the important thing is that life is much better than it was, and the status quo should be maintained. I wonder if the younger people in Kinmen will be like those I had spoken to in Taiwan proper. There I had quizzed “Strawberries”—the privileged younger generation, “soft and easily bruised,” as their elders huff—about whether they felt Chinese, or could envision a unified future with China. “We are huaren [ethnic Chinese], but there are huaren all over the world,” a 20-year-old college student in Taitung had said. “Singapore, for example. We’re different from the mainlanders; we live different lives.” It was mostly young people who occupied Taiwan’s legislature in the spring of 2014, during the Sunflower Movement, to protest what they saw as a dangerously close trade pact with China. Where they were concerned, this marriage—if indeed it was that—was best ended in divorce.

Much of the difference between the generations can be explained by education. President Chiang Kai-shek, followed by his son Chiang Ching-kuo, emphasized that Taiwan was Chinese, as a culture and as a state. He used mostly recently-emigrated mainlanders, or waishengren, in government posts, curtailed the use of the Taiwanese dialect, and required schoolchildren to learn the name of every province in their country: China. Shimu had told me that many people her age felt a special yearning for China after all the stories they were told of it in school. But with democratization in the late 1980s and 1990s, the local Taiwanese, or benshengren, who compose the vast majority of the population, reasserted themselves. Education now focuses more on the history of Taiwan itself. Time, too, has changed the way people think; for the new generation, the concern is jobs and stagnant wages, not taking back the mainland. Their sense of nation is defined by the practical reality in which they grew up. (“Taiwan is a country, just not a normal country,” said Lin Fei-fan, one of the Sunflower Movement leaders, on a visit to Cambridge, Massachusetts in August 2014. “Everyone wants to live in a normal country,” he added, a touch ruefully.) Then again, Kinmen has always been closer with China; perhaps young people here think differently.

Through an acquaintance who teaches geography at Kinmen High School, I arrange to interview students there. When I arrive on a rainy evening, Hong Xiangwen is waiting for me outside the student dormitory, long hair pulled back in a ponytail, wearing a tracksuit with the school’s name on it. She and a classmate both hold out their umbrellas, smiling shyly. Hong is 17 years old and bashful; she keeps ducking her head and burying her face in part of her collar. By contrast, her classmate Yang Xiaojun, a bright-eyed 17-year-old, “loves to talk,” as she tells me quickly. Soon we establish a rhythm as we sit at little chair-desks in an empty classroom: I ask Hong a question, then turn to Yang when she doesn’t seem to want to answer. Yang is very happy to help.

The parents of both girls are working across the Strait. Hong’s parents (a Taiwanese mother and mainland father who met in 1995, when Hong’s mother toured the mainland and her father was a tour guide) placed her here, she says, when she failed to test into the local junior middle school. Unlike many children of taishang (Taiwanese businesspeople), both she and Hong attended local mainland Chinese schools before coming here. It was, they tell me, utterly different.

“How was it different over there?” I ask.

“It’s a system of strict memorization,” Hong explains.

“And the teachers there are laoda, the Big Cheese,” Yang says. “They’ve got a strict system of enforcement, over there. You have to greet them with “Hello, Teacher,” and stand up when they come in; with the Taiwanese teachers, it depends. It’s more casual and friendly; some, we can call nicknames.”

As if to prove her point, a shy-looking man in his thirties with glasses and shaggy hair shuffles into the classroom, then stops short when he sees us. The girls look delighted, and call out to him teasingly. (“He’s our literature teacher,” explains Yang, giggling. “He’s very interesting!” Hong adds, giggling also.) The teacher mumbles, shuffling off to look for something at one end of the room.

Both girls came back a few years ago, and it wasn’t easy. On the mainland, they were Taiwanese, and back on Kinmen their classmates sometimes call them mainlanders. I asked them what identity they prefer, and both said quickly they were Taiwanese; Hong said her father supported her choice, “Maybe because I get a discount on the ferry ride that way,” she says, shrugging. “A lot of people want to go to Taiwan,” Yang says, of her Chinese classmates. But while on the mainland they had generally been considered cool, here it was the opposite. Mainlanders have left a bad impression, it seems.

“Mainlanders speak more rudely,” Hong says. Yang leaps out of her chair and begins to act out a scene in which someone has sat in her assigned seat on a bus. “If I’m a Taiwanese, I’ll say, ‘Excuse me, sorry, this is my seat,’” she says, using a gentle, sing-song, apologetic tone. Her partner in the role-play, another classmate, says quickly, “Oh I’m sorry!” and gets out of her seat.

“WEI!” Yang is now a mainlander, looking irritated, thrusting an arm at the unfortunate passenger who is in her seat. “Hey! This is my seat!”

“What are you speaking in a such a loud tone for? Who do you think you are?” comes the irritable rejoinder, and then they collapse into giggles, not used to hearing the mainland accents come out of their mouths.

“Why do you think there’s this difference?” I ask.

Yang offers the theory that mainlanders are spoiled only children because of the One Child Policy. Then again, she admits, the older people are like that, too. She doesn’t know why it’s different. “But that’s why Taiwanese don’t like mainlanders,” she finishes.

“And spitting, and littering. The environment over there is dirty,” Hong says, wrinkling her nose.

The young women both say they are taidu, pro-Taiwan independence, and had told their mainland classmates that when asked. “They didn’t seem to care that much,” says Hong.

“I attended a forum in which I interviewed a writer, a mainlander, really old, in his thirties,” Yang says excitedly. “After the interview we were just chatting and he asked me where I was from and I said Taiwan and he said, ‘Are you taidu?’ and I said ‘Of course,’ and he said, ‘We could finish you with one bomb,’” she narrates, waving a hand dismissively as the mainlander. “And I told him about all the blank spaces in the mainland’s version of history, especially about Mao Zedong and what he did. I said, ‘If you don’t believe me, jump the wall and look at these American websites!’”

Shi Qixuan, a 17-year-old boy who spent a couple of years in Guangdong and Xiamen as a child, wanders in. On his phone, he shows me the free software he has downloaded to “jump the wall” and look at mainland-blocked sites when in Xiamen. All three of the students use similar software. “Though it’s still slowed down sometimes,” Shi says. To keep in touch with Chinese friends, they use WeChat, a mainland app; for their Taiwanese friends, it’s the Japanese app Line. (There is an affection for Japan in Taiwan—another, not insignificant, difference with China. Taiwanese remember the Japanese mainly as relatively benign colonizers of the island from 1895 to 1945; in popular memory, they are much better behaved than Chiang’s Nationalist government which followed them.)

“Some older people on Kinmen have told me they feel Chinese,” I say. The cabbie who brought me over here, too, was a man in his late fifties who said warmly that after relations opened up again, it felt good to reconnect. “They’re one of us,” he had said, of people across the water.

They all start and stare at each other, as if this is quite a new statement, strange and amusing. To them, the Taiwanese identity is a given. But, Shi supposes reunification will happen sooner or later, at least that’s what a lot of Taiwanese say. “China’s so big and strong. That’s what everyone says,” he says shyly. “So I think it’s a matter of time.”

“Not necessarily,” says Yang. Her mind races ahead through the things Taiwan could try, how it could be stronger. “There are Japan and America. . .” And besides, she adds, her father says you have to consider the long-term consequences of reunification. If there were a world war, Taiwan would have no choice about whose side to be on. “Taiwan would become the frontlines because it’s stuck in the middle; you have to get through Taiwan to get to America,” she says. “Taiwan would be forced to be the frontlines.” It would be terrible, she adds; the island, stuck between giants, would suffer.

On Kinmen Island, it sounds like a familiar story.

* * *

Sim Chi Yin—VII Photo for ChinaFile The 30-minute ferries, which cross the Taiwan Strait, were launched in 2001 as part of the ‘Mini-Three-Links’ between China and Taiwan. More than 1.5 million passengers traveled by ferry in 2014 between Fujian, in China, and Kinmen. Since 2015, Chinese tourists traveling to Kinmen can easily get visas on arrival.

Towering over the main road that leads from Kinmen’s main city of Kincheng to the port where the ferries set sail for Xiamen, one passes a large billboard advertising Falun Gong, the “evil cult” that China outlawed in 1999. The broad, quiet golden fields are ruffled by the wind. A snowy egret sits on the back of a brown cow, both looking content.

People are boarding the ferry to mainland China carrying cardboard boxes of Kinmen Kaoliangjiu (an eye-watering 58-proof sorghum liquor) and snacks. Others pile in with large suitcases. Twenty minutes, perhaps a little more, bring us to the coast of Fujian province and the crowded towers of Xiamen. The sky has become whiter and harder to see through. The city’s newest towers press close to its edge, wrapped up in scaffolding; still incomplete. At their base, along the growing hem of the city, crane-like machines two or three stories in height bend busily, attending to something on the ground.

Enormous ships mow low through the water in front of our ferry, carrying naked islands of sand. Land reclamation, I will learn, has been conducted here since the 1950s. It continues now, an important part of the construction of a new international airport in Xiamen. A Dubai-style artificial island in the shape of cavorting dolphins, “Double Fish,” is also being built.

The first breath off the ship stuns. The air feels heavier in the lungs, and sharp with some unknown chemical taint. From the dock, we enter a large building. Funneled through customs, we emerge into a city that feels, as I pass through it in a taxi, like most medium-sized, booming Chinese cities: filled with gargantuan buildings which appear to be at most a decade old. Construction sites reach into the road, lined with Chinese Dream propaganda billboards. The cabbie says cheerfully, gesturing to the buildings around: “The officials have nice apartments, many apartments—and they have many mistresses!” It’s a smile and a complaint and a statement of fact all at once.

In Xiamen, a Chinese friend introduces me to her cousin, Mr. Gong. He is a musician, or rather, he creates music with software. He plays me a sample of something he is working on for the State Oceanic Administration (his employer, Little Egret Art Center in Xiamen, is a government work unit). When he presses a button on a computer in his office, the sound of crashing waves fills the room, accompanied by drums and violins. “It’s American software,” he explains.

The assignment is to create a piece of music on the theme of Chuanghai; roughly, “bravely venturing forth upon the seas.” Gong says it is to promote the new policy of developing a “maritime Silk Road.” The dramatic, swelling rhythm is supposed to reflect excitement about human exploration and triumph over obstacles. Most of his work, though, involves music for the Art Center’s dance troupe. It was this work that first took him to Kinmen in 2001, where the troupe gave a traditional Fujianese dance performance that emphasized the two sides’ shared cultural roots. They have given such performances across the world, he says, including on the island of Taiwan itself.

“What was your impression of Kinmen?” I ask eagerly.

“At the time, Li Zhufeng was running for county magistrate there. We saw him in the street shaking hands with the street-sweepers, saying”—he mimics the false sincerity of the politician’s tone, the fixed, teeth-baring smile—“‘The future of Kinmen depends on people like you!’ We mainlanders couldn’t stand it,” he says, making a face.

“Why not?”

“It was fake!”

Gong doesn’t like fake. He is a straight-talking Sichuanese, and the self-styled black sheep of the family. He favors black long-sleeved T-shirts and wears a baseball cap on his bald head. He tells me about being hosted by “rich locals” in Kinmen when a typhoon delayed his departure. “They said they’d like reunification—to be the back garden of Xiamen again. It may have just been something nice to say, or that some were businesspeople wanting to make money. They may have been more honest with you. . .”

I tell him most of the Kinmenese I’ve talked to say they want to maintain the status quo with China.

Gong nods. He does not seem to care very much about the prospect of reunifying little, “backward” Kinmen, as he recalls it. But he acknowledges, when I bring it up, that the spirit of chuanghai, or bold taking of the seas, cannot allow Kinmen to remain as it is forever. China, as Gong goes on to describe it, sounds like Gulliver on Lilliput: a giant in chains. Taiwan is referred to as part of the “first island chain” that binds China. If Taiwan proper is part of the first chain, one thinks, what is Kinmen, which is visible from the highway just outside?

Gong reminds me that this state of affairs is America’s fault. If it were not for Obama’s pivot to Asia and the planned Trans-Pacific Partnership, China would not feel so tightly hemmed in. (He forebears to mention America’s Seventh Fleet that once defended the Strait, and American aid to Taiwan, but it hangs there, a given.) I need to understand China’s history; I need to understand that for China, the worst thing that can happen is chaos, and this has always been precipitated by the incursions of foreigners. “The Americans are backing the Occupy Central protests in Hong Kong,” he says confidently. I ask him what his sources are, and he tells me there have been reports.

“I watch Phoenix Television; it’s from Hong Kong,” he adds, defensively.

Gong once believed in democracy—in all the ideals Taiwan supposedly embodies. “They’re a kind of mirror for us,” he says, the can’t-stand-it expression returning to his face. “Look how chaotic it is! People fighting in the legislature! Money in politics! Try democracy here, and votes would be going for 200 yuan a pop.”

What does he hope for, then, I ask. What does he want for his country, say in 40 years? (I have grown fond of the question.)

It takes a while for him to answer, and when he does, it isn’t direct. He says only that China has been through an enormous amount, and people are grateful for the stability and progress that has come in the past few decades. He says, “Deep down, I still have some of the same ideals you do, that some of my friends do.” Beyond this, he has nothing to suggest.

* * *

Sim Chi Yin—VII Photo for ChinaFile At the height of the Cold War, as many as 100,000 soldiers were barracked on Kinmen, outnumbering civilians. Today, there are only about 3,000 troops left on the island.

I am back on Kinmen, this time on Little Kinmen, or Heroes’ Isle, the smaller of the two main islands, and I am burning incense at the grave of a young woman called Wang Yulan. More officially, she is known as the “Chaste Maiden.” Kinmen is dotted with shrines to the unknown dead of the chaotic war years; this is one of the better-known. The grave, a disconcertingly fresh-looking large swell of earth next to a little temple, holds a female corpse that washed up nearby in the summer of 1954. According to Harvard historian Michael Szonyi’s portrait of Kinmen, Cold War Island, the dead woman’s spirit told her story thus through a local medium:

Sim Chi Yin—VII Photo for ChinaFile A foggy view of the bridge being built between Kinmen and Lieyu Island, seen from Kinmen’s spike-lined northwest coast at low tide.

My surname is Wang, and my given name is Yulan. I am from Xiamen, aged seventeen, from a poor family. . . [While] I was gathering clams at the seashore, brigands from the Zhu-Mao soldiers [i.e., Zhu De and Mao Zedong; in other words, soldiers of the People’s Liberation Army] surrounded me, [intending to] shame me. . . [I] tried every measure to resist. But the bandits’ bestial conduct was impossible to predict. . . [They stripped] me naked and threw me into the sea.

“Are you married? You can ask her for sons,” says the old woman who sells spirit money and incense, encouraging me to buy more. “She’s very ling, efficacious.”

I politely refuse; I haven’t decided if I want daughters or sons at all yet. The woman’s son, Mr. Hong, who looks to be in his sixties, is sitting to one side of the little temple, and I ask him about the introductory plaque at the temple’s entrance. It now makes no mention of “bandits.”

“Yes, that’s what it used to say, ‘Zhu Mao bandits,’” says Hong. He squints at the engraved black stone, which looks polished and fairly new. “Here, it says ‘Year of the Republic 84, so, 1995. That’s when it was changed.”

“Now it just says ‘lawless persons’?” I say, reading.

“Yes.”

I ask him about the change in Wang Yulan’s story: about 10 years ago, she reportedly declared, through another local medium, that she wanted to go back. She was not the only ghost to change her mind. Perhaps it is an indication that some people here want to be reunited with China?

Hong hasn’t heard this story.

Sim Chi Yin—VII Photo for ChinaFile Ask Kinmen residents what they feel about Xiamen and mainland Chinese and they might first point out that rubbish is floating over from them to Kinmen’s shores—complete with their simplified Chinese labels (in contrast to Taiwan’s traditional Chinese).

I excuse myself to wander off to the nearby beach, where I stand at the water’s edge and take photographs of Xiamen and of the barnacled anti-landing spikes planted in the sand. The spikes were meant to pierce the bottoms of People’s Liberation Army boats. They were not able now, however, to stem the influx of garbage. I walk further, past ragged lines of debris commensurate with the daily tides: an unopened pack of antibiotic capsules produced in Shandong, a plastic sanitary napkin wrapper, emptied containers of soy milk and instant noodles and boat-oil, chips of Styrofoam from the buoys that keep fish-nets in place, and a dead osprey, its elegant, spare wings outstretched like the last plié of a ballet dancer. Every object with writing on it has simplified Chinese characters, not the traditional ones used here. Still, I tell myself, perhaps it’s possible that locals buy products on the mainland and dump them. (A local woman soon sets me straight. “Look how clean we keep things here,” she says, gesturing to the immaculate, well-swept street on Little Kinmen. “We did not do that!” She gestures in the direction of the beach.)

When I return to Chaste Maiden Temple, I ask Hong about another source of tension between Kinmen and Xiamen: sand-stealing. “Is it true mainland boats come up to the coast here at night and extract sand to sell? The newspapers say it’s causing erosion on Kinmen,” I say.

“Yes, they do sand-extraction,” Mr. Hong says. “And some Kinmenese invest in it.” The owners of the boats, and the workers, are mainlanders, he explains, but some locals have put in some money, which they get back later, after the sand is sold. It is another reminder of how complex the cross-Straits relationship is, especially here. There are those who deplore the increasing closeness, and those who seek to profit from something that they believe cannot be stopped anyway. Sometimes they are the same people.

* * *

Sim Chi Yin—VII Photo for ChinaFile Windows look out of the L18 military bunker and fort on Lieyu Island, through which soldiers would have watched the coast and fired their rifles. Currently accessible only on foot, development plans have local activists saying any changes to the bunker would destroy its authenticity and grit.

Back on the beach, I climb inside an abandoned fort and peer through a rectangular machine-gun hole at the sea and at Xiamen. It is so close I can hear the buzzing of motorboats zipping along the Xiamen side. In that city, I met a man named Wu Houshui, who had been a P.R.C. intelligence officer there in the mid-1970s, assigned to watch Kinmen. A cabdriver with silver hair and a kind face, Wu pointed out the hill where he had once stood with binoculars, noting the planes flying in and out of Kinmen and the troop exercises on its beaches. Young and hungry for meat, he had eaten the tinned beef that floated over in the propaganda packages. Even then, he told me, he never thought of Taiwanese as the enemy.

“I liked Deng Lijun’s songs a lot,” he said, breaking into a smile. “They gave me a warm feeling toward people in Taiwan. The songs weren’t political—yes, it felt fresh. All of ours were political.” He had loved to sing since he was a child. Mostly he remembered the hymns of praise to Chairman Mao, but he sang me a bar or two of “Taiwan Compatriots, My Flesh-and-Blood Brothers.”

Wu was standing on his hill watching Kinmen in 1976 on the day that the fall of the Gang of Four was announced. Jiang Qing, wife of the recently deceased leader Mao Zedong, and her closest comrades, were now the enemies of the people; the Cultural Revolution was over. But Wu felt nothing. “It was just one more campaign: a person would be good, and then they would be bad and they would be beaten down, and a rival faction would be good,” he said. “We were numb.”

On the same day, across the water in Kinmen, another young intelligence officer named Lin Shih-yu heard the same announcement. It was his job to listen, standing on the beach with a notepad, to the wind-distorted voices from the mainland’s loudspeakers. “Suddenly, the Gang of Four was the enemy,” he told me in Taipei, where we met.

Lin lived under a dictatorship in the 1970s, too, but in Taiwan it was not one of perpetual revolution. In college, he and his classmates were able to find and mimeograph the writings of the country’s early pro-democracy reformers, waishengren from the mainland and benshengren with their roots in Taiwan, whom Chiang Kai-shek had jailed for their efforts. Lin was part of the successful democratization movement in Taiwan. In the 1980s, he was one of that first wave of Taiwanese businesspeople that Deng Xiaoping, China’s new leader, welcomed to the mainland to ease the transition to a market economy.

Lin had noticed a gap between himself and mainlanders his age. It made doing business difficult sometimes. Perhaps one of the differences, he said, was the amount of education. Despite pressing, he said little else; it was something he felt uncomfortable or maybe incapable of describing.

Perhaps it was education, or perhaps it was something more. The two sides have separate histories; China and Taiwan were never tied quite as closely as the pro-reunification narrative implies, and the past 66 years of separation have widened the gap still further.

Wu, the Xiamen taxi driver, was typical for his generation on the mainland, one that a contemporary of his in Chongqing had told me was the “most unlucky.” (“When we were young and growing, in the early 1960s, we met with famine. When we wanted to go to school, we met with the Cultural Revolution. When we wanted to have children, we were allowed only one,” he had said.) Wu remembered, without any apparent bitterness, the destruction of his family’s ancestral hall in Jiangxi. He remembered reporting aloud to Mao’s portrait as soon as he got home, lest people watching report him. “Your family might not report you if you didn’t do it, but other people would,” he said. “Trust between people was destroyed.” His ancestral hall has since been rebuilt, as have those of other families. But some things that were lost are harder to rebuild. Trust between people. Faith in politics. For Wu, lessons imparted by the Cultural Revolution still hold true. “Politics is really no different,” he told me. “This anti-corruption drive: it is Xi Jinping aiming at rival cliques.” One of the last things he said to me, with a resigned, wise, and weary smile: “It’s very hard for ordinary folk to tell the future.”

Lin Shih-yu does have faith in politics. The young man who had stood across the way from Wu, on Kinmen, he has recently decided to devote all of his time to the new Taiwan Citizen Union, which he helped to organize. It will, he said, help to pressure established parties like the KMT and DPP to make changes. (The Taiwan Citizen Union has since split into two: the Social Democratic Party and the New Power Party, both pro-independence. The NPP won five parliamentary seats in the January 2016 elections that also delivered the presidency to the DPP’s Tsai Ing-wen.) “The DPP is becoming corrupt, too,” he says. It is important, he believes, to keep fighting for change.

* * *

Sim Chi Yin—VII Photo for ChinaFile A military history enthusiast, Chen Zhixuan, stands atop the L18 military installation on Lieyu Island, overgrown with shrubs. Chen joined a group of Kinmen residents to explore the installation and clean the nearby beach of litter that had floated in from the sea.

On a final visit to the ferry dock in Kinmen, I stop at the port’s Harbor Office, just within the main building where the ferries to the mainland come and go. Why is it, I ask, that I hadn’t seen any Republic of China flags flying on the Taiwanese ferries in Xiamen? “I saw People’s Republic of China flags on the ferries docked on the Xiamen side,” I explain to the trio of uniformed young men behind the counter.

The men, looking pleased and bashful under large-billed caps, all smile. “You may not have noticed, but the mainland boats aren’t flying flags when they arrive,” one of them says. “They stop flying the national flag at the halfway point, as do we.”

When I ask if this is a rule, all three of them laugh and shake their heads. “No, no, not a rule. It’s a kind of moqi. A silent understanding.” Gong, on Xiamen, had used the same word—which implies a kind of intimacy and seamless cooperation—to describe the way in which Xiamen and Kinmen gradually began coordinating their Chinese New Year’s fireworks so that people on both sides could enjoy a combined show from their beaches. When Gong used the word moqi, he used it as evidence of an unbroken bond: of something that was meant to be.

“Yes, it’s moqi. We respect each other,” beams one of the officers, watching the next batch of visitors flow into Kinmen’s port. “The two countries respect each other.”

Real love stories are possible now, Weng had said, because mainlanders and Taiwanese speak the same language. Sometimes, though, using the same language is not enough; even the same word, moqi—silent understanding—is understood differently. The young Taiwanese officers see two countries being polite to each other; China sees two parts of the same country moving closer.

On one level, experiments in cross-strait closeness are working on Kinmen. Taiwanese citizens there take the ferry over to mainland China on weekends and collect rent on their properties in Xiamen; mainlanders buy cups of Mao Zedong Milk Tea, laced with Kinmen’s famous liquor, and sip them at the round stone tables of the Wind Lion God Café in Shuitou. Sometimes they order the Chiang Kai-shek Milk Tea, filled with sweet jelly cubes. In taxis and on docks they chat together about politicians, history, the price of liquor. And they marry, sometimes. But in important ways, the gap between them is widening. Thinking back to Shimu’s description of China and Taiwan as an estranged couple, I imagine them sitting in the same room. They are talking to each other across the gap, smiling at each other. But each is preoccupied with separate thoughts. China thinks of breaking out of its chains. Taiwan, its “treasure island,” must be reclaimed, and the seas round it opened. This is China’s right, and a righting of past wrongs. Taiwan, meanwhile, is thinking about a future of presidential elections and diplomatic balancing; of the lessons of Hong Kong, and how best to play it smart. When the two sides speak to each other, the messages become warped. A Taiwanese complains about vote-buying and fights in the legislature; a mainlander hears repudiation of Taiwan’s system. One side says “peace across the straits,” the other, “peaceful reunification,” and, still smiling, they gloss over the difference. For now.

If this is marriage, it is one described by the Chinese proverb mao he xin li: “the appearance coalesces, and hearts go their separate ways.” The gulf that separates Taiwan and China is at its narrowest point on Kinmen, the place from which contradictory messages still flow: love songs and water demons, poisonous air and life-giving water, a history of war and a history of love. The gulf grows wider with each generation: it will take more than these new links—or even a peace bridge—to span it.