Shinri Shioura set a Japanese record in the men's 50-meter freestyle on Sunday, the sixth day of the national championships.
Shioura touched the wall in 21.67 seconds in his semifinal at Tokyo Tatsumi International Swimming Center, trimming 0.2 off the record set last year by Katsumi Nakamura.
The 27-year-old Shioura was a member of Japan's bronze-winning 4x100 medley relay team at the 2013 world championships in Barcelona. He also won gold in the 100-meter freestyle and the 4x100-meter relay at last year's Asian Games in Indonesia.
The weeklong national championships also serve as a qualifier for this summer's world championships in South Korea.