Some thrilling finals were set up on the penultimate day of Japan nationals and trials in Tokyo, where the depth in quality of fields speaks volumes about why Australia considers the Japanese to be a threat to its world No2 position behind the United States in the race pool.

In finals, it was not quite the 1:52.51 of yesteryear but on 1:55.52, Ryosuke Irie, one of the most aesthetic technicians in world swimming, claimed the Japanese title, booked his passage to Pan Pacs in August and now lays claim  to the best three performances so far in 2010.

In the men's 100m breaststroke heats quadruple Olympic champion Kosuke Kitajima led the way on 1:00.89, with the next seven men between 1:01.31, for Ryo Tateishi (50m and 200m champion) and 1:01.92. A thriller in prospect. The semis did not disappoint:  King frog claimed lane 4 with a 1:00.41 effort ahead of challenger Tateishi, on 1:00.95. The next seven men raced between 1:01.13 and 1:01.98, with Hiromasa Sakimoto the ninth man and out of the final.

After finishing second in the 50m and 4th in the 200m at nationals in Tokyo, Kitajima may have developed enough hunger to put his foot down.

Tokyo trials, day 5 race reports:

Women's 800m freestyle

Maiko Fujino clocked 8:34.91, just outside best, to win what until 600m was a very close contest with Yumi Kida, who slipped back a little over the closing 200m before taking silver in 8:36.78, again, just outside best. The fastest finisher in the race was 16-year-old Asami Chida, who produced a last 100m split of 1:02.16 for a 8:37.86 total. 

That put Chida just outside the Japan all-time top 10, up from 27th on a best time from January this year of 8:43.16. The future rarely waits long.

Women's 200m backstroke

National records are off the menu this season for most of the best any nation has to offer, but Aya Terakawa fell just 0.11sec shy of her lifetime best, set in Rome 2009, with a 2:08.60 victory over Shiho Sakai, on 2:08.79, 0.05sec shy of her lifetime best from June last year. In third was 15-year-old Marie Kamimura, 2:10.49, a second outside her 2009 best as one of the fastest 14-year-olds in the world last year.

Men's 200m backstroke

Not the 1:52.51 of yesteryear but on 1:55.52, Ryosuke Irie claimed the Japanese title, booked his passage to Pan Pacs in August and now lays claim  to the best three performances so far in 2010. His best was a 1:55.11 in Osaka in February, while a 1:56.81 in semis in Tokyo yesterday is better than the second-best man in the world so far this year, Britain's James Goddard, on 1:57.06.

Only three men have ever gone faster than Irie when wearing a textile suit:  Americans Ryan Lochte, Aaron Peirsol and Michael Phelps.

The silver in Tokyo went to Kuninori Tada, on 1:58.84, an effort that locked Kosuke Hagino off the podium by 0.11sec.

Semi-finals

In the women's 100m breaststroke, 14 women raced inside 1:10. At the helm, Satomi Suzuki claimed lane 4 for the final in 1:08.56, with Fumiko Kawanabe and Mina Matsuchima also inside 1:09, on 1:08.67 and 1:08.78 respectively.

Another tight final was in prospect in the men's 200m butterfly, with Hidemasa Sano, on 1:56.40, taking lane 4 by just 0.01sec ahead of 2005 world titles silver medallist Takeshi Matsuda. Only 0.22sec away was Ryusuke Sakata, on 1:56.63, followed by five men below 1:59. The depth of Japanese swimming is something to behold.

Takurou Fujii led the way in the 100m free for men, on a 49.12 that looks solid indeed in the light of events in France, where he would have finished third in the final at Saint-Raphael. In Tokyo, his main challange comes from Yoshihiro Okumura, on 49.70.

Haruka Ueda claimed lane 4 for the final of the 100m freestyle in 55.06, with Yayoi Matsumotio next through on 55.16. In the 200m butterfly for women, Natsumi Hoshi claimed lane 4 for the final in 2:10.09,  ahead of a 2:11.96 for Naoko Matsuga.