Rikako Ikee rewrote her national 100-meter butterfly record for the second straight day on Wednesday, the second day of the Japan Swimming Championships.

Ikee booked her spot on Japan's team for this summer's Asian Games in Jakarta and for August's Pan Pacific swimming championships by winning the 100 in 56.38 seconds, breaking the record she had set the day before at Tokyo's Tatsumi International Swimming Center.

"This isn't the final stage," said the 17-year-old Ikee after winning her third straight national 100 butterfly title.

"In this summer's meets, I want to do well and surpass this time. I have three more events here and I want to do my best so that I swim well in each of them and set national records."

Kengo Ida won the men's 50 butterfly in a Japan record 23.40 to secure his first national title, a time the 26-year-old was not expecting.

"It's not possible," he said of the nine-year-old record that had been set before high-speed suits were outlawed. "I guess this result comes from my focus on simply swimming the race my way."

At the other end of the experience spectrum, Yasuhiro Koseki won his fifth straight 100 breaststroke title 59.30, while fellow veteran Ryosuke Irie swam the 100 backstroke in 53.18. He also won for the fifth straight time.