In Western culture, 13 is considered an unlucky number. For Koji Murofushi, Japan's maestro of the hammer throw, it's not a symbol of misfortune; it's a number that underscores one thing: his era of dominance.

News photoKoji Murofushi, a 13-time champion in the hammer throw at the Japan Athletics National Championships and a 2004 Olympic gold medalist, is one of the favorites in his event.

AP PHOTO

Last month, Murofushi picked up his 13th straight national title in the men's hammer, capturing the gold medal at Nagai Stadium.

Murofushi returns to the Osaka stadium for the 2007 IAAF World Athletic Championships, which get under way on Saturday.

The hammer qualifying is slated for Saturday night at 7:30, followed by Monday's final at the same time.

"Right now my fighting spirit and my confidence are so strong, I am very confident going into the World Championships," Murofushi, the 2004 Olympic champion, said in a recent interview with the Chinese press.

A year away from the Beijing Summer Olympics, the Osaka competition serves as a big-time showcase for hundreds of athletes looking for a measuring stick of where they are in their preparations.

Murofushi's top throw of 2007 (79.24 meters) is respectable, but not a medal-contending statistic. Vadim Devyatovskiy of Belarus owns the top mark of the year (82.94) to date.

Murofushi, however, is more acclimated to Osaka's humid summer heat and the conditions at Nagai Stadium.

The 32-year-old Murofushi, whose father Shigenobu was a national legend in his younger days, was the 2001 World Championships silver medalist and '03 bronze medalist, but skipped the '05 meet due to injury.

Sprinter Shingo Suetsugu, the bronze medal winner in the 200-meter race at the 2003 World Championships in Paris, returns to the big stage for another shot at gold.

His season-best time of 20.20 seconds is the 25th-fastest time of 2007. Tyson Gay's 19.62-second effort is No. 1.

Dai Tamesue, a two-time bronze medalist (2001 World Championships in Edmonton, Alberta, and 2005 in Helsinki) in the 400-meter hurdles could add a third medal to his collection.

Pole vaulter Daichi Sawano cleared 5.75 meters at a Shizuoka meet in April, putting him in the mix with the world's best. American Brad Walker is tops this year with a mark of 5.95 at a March meet in Brisbane, Australia.

In Saturday's meet-opening event, the men's marathon, expect Osaka's Satoshi Osaki to be a crowd favorite. He is joined by a pair of talented teammates — Tsuyoshi Ogata, who ran to a third-place finish at worlds in 2005, and Toshinari Suwa, who finished sixth at the Athens Olympics — as well as Mitsuru Kubota and Tomoyuki Sato in representing the national team.

Kenji Narisako was the 2006 Asian Games winner in the 110-meter hurdles.

All told, there are 45 male athletes on Japan's national roster.