Mai Nakamura broke the world record in the women's 50 meters backstroke while Masami Tanaka completed the Japan Swimming Championships in "perfect" style on Sunday, clocking national records in all seven of her breaststroke races.
Nakamura bettered the previous world record, set by Spain's Nina Zivanevskaya at the Spanish Championships on April 8, by 0.02 of a second, finishing in 28.67.
"When I looked at my time in the first half of my 100-meter race, I thought I could make it," Nakamura said.