Takeshi Matsuda won a freestyle-butterfly double in a single day for the second straight year Friday, while Olympic champion Ai Shibata claimed her second title in as many days at the national swimming championships.
Matsuda won the men's 1,500-meter freestyle in 15 minutes, 18.23 seconds and then came back to show his versatility at the Yokohama International Swimming Pool, taking the 200-meter butterfly in 1:56.28.
Matsuda met the qualifying standard for this summer's world championships set by the Japan Swimming Federation in the 200-meter butterfly along with runnerup Ryuichi Shibata, who clocked 1:56.84.
Freestyle swimmer Shibata, the women's 800-meter gold medalist in Athens last summer, followed her triumph in the 400 with victory in the 200 in 1:59.57, beating Norie Urabe by 0.91.
In other races, Olympic bronze medalist Tomomi Morita cruised to his fourth straight national crown in the men's 100-meter backstroke in 54.36, coming within 0.11 of his own national record.
Hidemasa Sano captured his first national title with victory in the men's 400-meter individual medley in 4:16.60.
In the women's 100-meter backstroke, Hanae Ito held off Athens Olympic 200-meter bronze medalist Reiko Nakamura by 0.20 to win in 1:01.15.
In addition to the men's butterfly pair, seven swimmers, including Morita, Sano and Ito, were guaranteed their places in the world championships to be held in Montreal in July.
On Thursday, double Olympic champion Kosuke Kitajima finished third in the men's 200 meters behind Genki Imamura and Daisuke Kimura, and failed to win a place for the discipline in the world championships.