RIKUZENTAKATA, Japan -- When the tsunami warning sounded, workers at the two-centuries-old soy sauce maker in northeastern Japan ran up a nearby hill to a shrine for safety, and watched in disbelief as towering waters swallowed their factory.

They all believed the business, started in 1807, and its precious fungal cultures that give soy sauce its unique taste were lost forever. Everyone except for Michihiro Kono, the ninth-generation son of the founding family.

Four years later, Yagisawa Shoten Co. has been saved through Kono's conviction, crowd-funding and the unexpected survival of its vital ingredient.

"If you don't give up, no matter how painful it gets, there will always be a way," said Kono, 41.

The March 11, 2011, tsunami killed nearly 19,000 people and set off meltdowns at a nuclear plant in the prefecture of Fukushima. In Rikuzentakata, Iwate Prefecture, where Yagisawa is based, nearly 1,800 people were killed as sweeping waters reached as high as 17 metres. Four years later, some 4,000 people still live in temporary housing in Rikuzentakata, mostly makeshift garage-like buildings.

Taking over as president from his father shortly after the disaster, Kono kept the company going even when it didn't have a single product to sell. The tsunami wiped out not only the factory but also the entire inventory. The damage was estimated at 220 million yen ($2 million).

As word of historic Yagisawa's plight spread, it got a lifeline from crowd-funding site Music Securities Inc. in Tokyo, which raised 150 million yen ($1.5 million) from sympathizers across the nation. Each supporter gave 10,000 yen ($100), half of it as investment and half as a straight donation. The company also got some government aid.

"We are a company in the boondocks and so we didn't know that much about crowd-funding. We did not have a very good image. We thought of takeovers like vulture funds," said Kono. "But it turned out to be a great system for a company like us."

From the start, Kono kept paying the salaries of his 38 workers, more than half of them women, and initially asked them to do volunteer work, distributing emergency food and clothing to tsunami victims. He believed a person without work would lose the mental energy to keep going.

Kiyoko Araki, 55, who lost her sister to the tsunami and still lives in temporary housing, recalled how grateful she was she could keep busy. These days, she is happily packing boxes with bottles of soy sauce for shipment.

A pungent scent wafts from the nearby six-ton vats filled with the dark sauce. What's wonderful about soy sauce-making is that it takes so long to make each product, each process requiring handcraft-quality care, Araki said.

"And soy sauce is seasoning every home needs," she said proudly.

Six other Yagisawa employees lost a family member to the tsunami. One employee died while doing his work as a volunteer fireman.

By May 2011, Yagisawa was selling soy sauce again, but products made by other manufacturers. Kono turned an old inn in Rikuzentakata into his office and then built a new factory in a nearby town on land vacated by a school. It began soy production in early 2013.

But resurrecting Yagisawa's soy sauce flavour would not have been possible if the original cultures had not been found, mainly by sheer luck.

The cultures were in storage at a university medical research laboratory where Kono had donated them for possible cancer-fighting research. The lab was destroyed by the tsunami, but the containers with the cultures were found nearby by its researchers, intact.

The sauce, made from soy beans and wheat, must sit for two years before it can be sold. That's why the sauce, given the name "Miracle," went on sale for the first time only in November.

These days, the company is still losing money, but sales are back to about 70 per cent of pre-disaster levels, and it has found new customers including a fancy restaurant in France. Before the tsunami, it had mostly supplied businesses. Now, it's selling more soy direct to consumers, many of them eager to help a company rebuild.

Still, the success of Yagisawa is an exception to the prevailing story of loss and death the tsunami has left.

The Rikuzentaka coastline that used to be filled with quaint storefronts like Yagisawa's and residential homes is now a barren stretch of brown dirt, except for trucks and cranes.

A memorial replica of a solitary pine tree that survived the tsunami is perched on top of a hill, a symbol for the city. But there are hardly any visitors.

Rubble and debris have been cleaned up. Construction work is underway, razing nearby hills, moving the dirt with conveyor belts that stretch for nearly two miles (3 kilometres), and stacking the dirt into mounds.

The goal is to raise the shoreline by 9 to 11 metres (30 to 36 feet) above sea level, and rebuild a community in the tsunami-zone, on top of the elevated area, a project expected to take three more years.

Kono acknowledged he was skeptical about the effort, noting that neighbouring towns had offered to take Rikuzentakata residents in.

But he plans to be right back with a store, maybe a restaurant, when the project is finished. He has already opened a small cafe in the construction area, selling soy cakes, Yagisawa T-shirts and a variety of soups, pastes and sauces, including "Miracle."

Mamoru Araki, 41, owner of one of a handful of restaurants left in the area, who grew up with Kono, said Yagisawa sauce is not too sweet, just right for his sashimi, or raw fish.

Big challenges remain for reconstruction in the region, but at least his friend's company was back.

"That taste has returned," he said.