Yamakawa studied Japanese calligraphy when he was a child — from kindergarten until he was about fifteen. He made it to 8-dan before quitting.
Source: Sponichi 8/29/2017
Yamakawa filed marriage papers with a twenty-seven-year-old woman, who was one-year ahead of him at Fuji University, on August 9, 2017. The two celebrated their seventh year together on August 9.