Photo/Illutration Hiroaki Suga, a “kikanshi” engineer, mixes hot spring water from different sources to supply 42-degree water to the Dogo Onsen Honkan main bathhouse in Matsuyama on March 15. (Takeshi Kamiya)

MATSUYAMA—Hot water deep underground for several years or even decades makes hissing and whirring noises as it snakes its way to the surface through a series of pipes.

The water from several sources emerges at a supply facility on a hill overlooking the Dogo Onsen Honkan, the main wooden bathhouse of an ancient hot spring resort here in Ehime Prefecture.

The rising water tests the precision skills of a city worker tasked with making conditions ideal for bathers.

“My job is to mix hot spring water of different temperatures and supply it to bathtubs in Honkan so that it will be exactly 42 degrees there,” said Hiroaki Suga, 46, a “kikanshi” engineer of more than 20 years.

The bathhouse fully reopened on July 11 for the first time since 2019, when preservation and repair work began to make the building quake resistant.

The resort is managed by the Dogo Onsen Office.

WATER BARISTAS

Kikanshi have been likened to coffee baristas because of their dedication and attention to detail.

There are 29 hot spring sources at the Dogo city-run resort, 18 of which are still usable.

The No. 4 facility there collects water from 17 sources, whose temperatures range from 20 to 55 degrees. No outside water or heat is added to the spring water at the surface.

Suga blends the spring water at a slightly higher temperature at the supply facility because the water cools when it passes through pipes connected to the main bathhouse.

The level of cooling depends on the season and the weather. The temperature of the bathtubs also drops during the night after they are emptied.

The engineer checks the bathtub temperatures and the weather to determine how hot the water should be. He then sends the blended hot spring water at 3:30 a.m., two-and-a-half hours before the Honkan building opens at 6 a.m.

“Some customers say they can tell a temperature difference of 0.1 degree,” he said. “It is rewarding when they say, ‘It was a good bath.’”

ENSURING WHAT’S NATURAL

Born and raised in Matsuyama, Suga thought about becoming a public servant after graduating from college. He happened to find a job offer for kikanshi on the internet.

The Honkan bathhouse, rebuilt in 1894, is designated as an important cultural property by the central government.

“I thought it was wonderful to be involved in hot water-related work at the cultural property,” Suga said.

He became a city worker in 2001 when there were six kikanshi. Now, there are five.

As an apprentice, he used machines to mix the hot spring water to a desired temperature instead of resorting to the methods taught by his older colleagues.

Suga began working on his own about one month later.
He was nervous when he sent the hot spring water to the main bathhouse for the first time at 3:30 a.m. that day.

“I wasn’t sure whether I could make it in time for the opening hour, or whether I could achieve the right temperature,” he said. “It is taken for granted to operate the bathhouse without trouble. But I was wondering if there would be a day when I could do so on a routine basis.”

At the time, the temperature of the bathtubs was set at 43 degrees. The temperature was later decreased to the current 42 degrees in consideration of the rising number of foreign tourists.

ONCE-IN-A-LIFETIME VISIT

During the five and a half years of renovations, the amount of hot spring water supplied to Honkan increased to 2,000 tons a day from 1,700 tons.

The resort is said to be the only non-volcanic hot spring area that can produce at least 1,000 tons of groundwater daily.

Still, the amount is not as large as volcanic springs that are close to heat sources, said SugaX, adding that the Dogo Onsen resort water is finite.

“It is also important for kikanshi to pay attention to the supply amount to Honkan, hotels and other facilities, and manage the distribution to prevent excess strain on one hot spring source and causing it to dry up,” he said.

He continued: “For some customers, it could be a once-in-a-lifetime visit to Dogo Onsen. That is why we want to keep maintaining the spring sources and the hot water supply.”

Related News