In early-morning subzero temperatures, revelers wearing loincloths throw hot water at one another at the Yukake Matsuri festival in Naganohara, Gunma Prefecture, on Jan. 20. (The Asahi Shimbun)

NAGANOHARA, Gunma Prefecture--Getting doused with buckets of water on a frigid winter morning isn't for the faint of heart, but luckily for the scantily clad participants at the Yukake Matsuri festival here, the water was hot.

The festival, where local revelers wearing only loincloths splash each other with water, was celebrated at the Kawarayu onsen hot spring resort in the early morning hours on Jan. 20.

Amid freezing minus 7 degrees temperatures, the annual festival was held for the first time after Yamba Dam began holding water. The dam will be completed in the spring.

The festival is staged around Jan. 20, said to be one of the coldest days of winter, every year. At the onsen resort, 50 participants, divided into red and white groups, douse each other with hot water while shouting, “Let’s celebrate!”

The festival is believed to have its origins from the hot water gushing out from hot springs that had almost dried up. Local people threw hot water on one another while crying out, “Hot water appear!”

The onsen resort was relocated to higher ground because of the construction of Yamba Dam. The dam, which had been storing water on a trial basis since Oct. 1, rapidly reached full capacity during Typhoon No. 19 later that month. The water level in the reservoir remains high.

Shozo Hida, 55, chairman of the Kawarayu onsen hot spring association, said, “In the year when the dam will be completed, we were able to hold this important local festival that has been passed down from generation to generation at this onsen resort.”

Nearly 70 years have passed since planning for Yamba Dam began. During that time, the number of residents of the onsen resort has decreased. The five hotels that remain are only a quarter of the number at the resort's height of popularity.

(This article was written by Munetake Tanno and Kohei Morioka.)