Having just turned 32 a few days before, boxer Shinsuke Yamanaka said with a bitter smile that having a birthday for an athlete at his age wasn¡¯t necessarily a pleasant thing.

But he added that he felt no decline whatsoever, but rather has room to improve to become a better fighter.

The WBC bantamweight champion, who¡¯s taking on Suriyan Sor Rungvisai of Thailand at Yoyogi National Gymnasium Annex next Wednesday, said that he¡¯d added variations to his boxing techniques and that¡¯d give him a stronger mental edge during a fight.

His ultimate blow, however, is still his potent straight left, which has been described as ¡°God¡¯s left¡± and given him international recognition in boxing circles, and the fans expect a knockout victory as Yamanaka has always done in the past.

Yamanaka, who¡¯s posted 21 wins (16 KOs) against zero losses, has defended his title six times, and he¡¯s done it with KO wins in the last five. If he sends Suriyan, a former WBC super flyweight champion with a 37-5-1 career record, onto the canvas, he will equal former WBA light flyweight great Yoko Gushiken¡¯s Japanese record for consecutive KO wins in world title matches.

¡°I¡¯m not aware of the consecutive KO-win record,¡± Yamanaka said at a public workout for the media at Tokyo¡¯s Teiken Gym on Tuesday. ¡°But I am aware of winning (in the Suriyan bout) in a KO.¡±

Meanwhile, you might wonder why his opponents still take Yamanaka¡¯s left, though it¡¯s clearly his best weapon. But Yamanaka claimed that he hasn¡¯t stayed at the same level, saying, ¡°I¡¯ve improved every fight (with my left), especially my balance has gotten better with it.¡±

But as much as he¡¯s put an enormous amount of effort to polish his lethal blow, perhaps it¡¯s a God-given ability.

Tsuyoshi Hamada, a former WBC super lightweight champion and a representative of Teiken Promotions, said that he didn¡¯t remember any other Japanese champions who have had as much of a definitive punch as Yamanaka¡¯s left.

¡°(Yamanaka) had it when he joined (Teiken), though I don¡¯t believe he¡¯d recognize it himself,¡± Hamada said. ¡°But he got to know it before he won the Japan title (in 2010).¡±

Hamada added that Yamanaka, a native of Shiga Prefecture, became a world champion-caliber fighter when he was still a four-round fighter.

Shin Yamato, Yamanaka¡¯s trainer, said that the boxer had recently bought him new custom-made punch mitts that are harder than usual mitts, but Yamanaka¡¯s left stings one particular spot on the mitts and damages his palms.

¡°That¡¯s something only Yamanaka can do,¡± Yamato said.