In Japanese, the word is johatsu, or "evaporated people."

Tormented by the shame of a lost job, failed marriage, or mounting debt, thousands of Japanese citizens have reportedly started leaving behind their formal identities and seeking refuge in the anonymous, off-the-grid world.

That's according to a recently-published book called "The Vanished: The 'Evaporated People' of Japan in Stories and Photographs," by French author-photographer pair Léna Mauger and Stéphane Remael. The book features a collection of vignettes from people who have fled modern society in search of a more secretive, less shame-filled life.

Mauger and Remael spent five years traveling around Japan beginning in 2008, earning the trust of locals to learn about the troubling trend. They also met the loved ones of those who disappeared: abandoned fathers, housewives, and ex-lovers. No formal government data exists on the trend, but by the pair's research more than 100,000 people "disappear" annually.

None of these people physically vanish, per se; the "evaporation" is more of an administrative disappearance. Similar to those in the Witness Protection Program in the US, johatsu opt to change their names, addresses, and business ties. They can essentially wipe the slate clean.

In Japan this escape can be surprisingly easy, Public Radio International reports. Japanese privacy laws give citizens a great deal of freedom in keeping their whereabouts under wraps. Only in criminal cases can the police mine people's personal data, and relatives can't look up financial records.

As Mauger told The New York Post in December, the disappearing acts stem from Japan's pressure to save face.

"It's so taboo," Mauger said. "It's something you can't really talk about. But people can disappear because there's another society underneath Japan's society. When people disappear, they know they can find a way to survive."

Johatsu cases seem to have emerged in the late 1960s, bolstered by a 1967 film called "A Man Vanishes," in which a man abruptly leaves behind his job and fiancee to disappear. In the 1970s, more cases emerged of young, rural-bred workers escaping harsh jobs in big cities, says Hikaru Yamagishi, who studies political science at Yale.

One man that Mauger and Remael met said it was his job to move these johatsu to faraway towns and cities during the 1990s. He and others like him called themselves a "night movers." It was their job to shuttle people to new, undisclosed locations under the cover of darkness. According to PRI, the 1990s were a booming time for such night moves. The economy had just crashed, and many people were looking for a way out.

"It's a crazy thing, but disappearance became a business at that time," Mauger told PRI.

In their book, Mauger and Remael also shed light on the loved ones who get left behind. Often, the families of johatsu said they wish the missing person had not felt so ashamed.

"We simply want to hear from him, he doesn't have to come home. If he needs money, we'll send it to him," a parent of a johatsu told Mauger and Remael.

The Japanese pressure to save face manifests itself in other ways, too.

For instance, Japanese has a word to describe suicides driven by overwork: karoshi. Last October, a report found that more than 20% of people in a survey of 10,000 said they worked at least 80 hours of overtime a month. Half of all respondents said they give up taking paid vacations.

In recent months, the Japanese government has taken small steps to reduce cases of karoshi, such as encouraging companies to let their staff work shorter hours on Friday. According to experts, however, the culture of work is so strong that many feel the incentives still don't outweigh the downsides of dropping out.

That is, unless they go the way of johatsu and walk away for good.