Banya Sokol on Geary Boulevard between 28th and 29th is the last Russian banya, a wood-fired traditional sauna, in San Francisco. There were four in 1989. There are not three. There is one. Yuri Kraevski, 81, has run it since 1965.

Yuri came to San Francisco from Leningrad with his parents in 1963 at the age of 19. His father, who had been a sauna master in a Leningrad neighborhood since 1948, opened Banya Sokol in 1965 with a partner who would die of a heart attack in 1971. Yuri took over the operation completely that year and has run it alone or with one staff member ever since.

The stove is wood-fired. Birch logs, sourced from a supplier in Oregon since the 1990s. Yuri lights the fire at 4 p.m. for a 6 p.m. opening. The room heats to 180-200°F over those two hours. The temperature has not gone below 170°F during opening hours in 19 years.

The banya is open Tuesday through Sunday, 6 p.m. to 11 p.m. Closed Mondays for cleaning. A session costs $42. A massage costs $80. Yuri does the massage himself, sometimes; younger masseur Igor does it the rest of the time. The same regulars have come for years. The senior regular, a man named Mikhail, has been coming twice a week since 1979.

“You cannot rush wood,” Yuri says. “The fire decides when. We sit and wait.”

The interior is two small rooms. The main sauna room, paneled in pine darkened over six decades. The cold plunge tub in the next room, kept at 48°F. A small lounge with a kettle for tea, a chess board missing two pawns, and a wall of black-and-white photographs of Yuri’s father and uncle in front of the original 1965 storefront.

In 2017 a developer approached Yuri offering $2.4 million for the building, the business, and the right to use the Banya Sokol name on a wellness chain. Yuri refused. He gave the developer one cup of tea and asked him to leave. The developer left. The offer has not been renewed.

On the Thursday I visited at 6:51 p.m., five men were in the sauna. They were ages 38 to 81 (Yuri was the 81). They spoke a mixture of Russian and English. Yuri threw a ladle of water on the rocks at 7:08 p.m. The steam rose. One of the younger men gasped audibly. Yuri laughed without smiling. The conversation moved on.

Yuri’s nephew Lev, 47, has been training with him for three years and will eventually take over the banya. The wood supplier and the cold plunge water and the chess board with the missing pawns will, by their agreement, stay exactly as they are.