Luis Nery was overweight and stripped of his bantamweight world title on Wednesday, one day before he was scheduled to defend the belt in a rematch with former titlist Shinsuke Yamanaka at the Ryogoku Sumo Arena in Tokyo.

Nery was way over the 118-pound bantamweight division limit. On his first attempt, Nery weighed 123 pounds. He was given two hours to see how much weight he could lose. When he returned to the scale, he was 121 pounds, and the title was declared vacant. Yamanaka weighed 117.5 pounds.

The fight will go on, but should Nery win, the title will remain vacant. If Yamanaka is victorious, he will regain the title.

The fight is a rematch of their bout from Aug. 15, in Kyoto, Japan, where Nery knocked out Yamanaka in the fourth round to win the title.

However, Nery (25-0, 19 KOs), a 23-year-old southpaw from Mexico, failed a Voluntary Anti-Doping Association-administered drug test as part of the WBC's Clean Boxing Program. He tested positive for the banned substance zilpaterol in a sample provided on July 27 in Tijuana, Mexico, his hometown, but the result was not known until after the fight with Yamanaka.

Nery claimed he had ingested contaminated meat, and after investigating the matter, the WBC issued a ruling in which it said that it believed the positive test result was indeed a result of food contamination. While the WBC did not strip Nery of the title, it did order him to give Yamanaka an immediate rematch.

Yamanaka (27-1-2, 19 KOs), 35, a southpaw from Japan, had made 12 successful title defenses before he faced Nery and was bidding for No. 13, which would have tied the Japanese record for world title defenses set by International Boxing Hall of Fame former junior flyweight champion Yoko Gushiken, who established the mark in 1980.

Now Yamanaka aims to reclaim his old title.

"This championship belt is for my newly born daughter in December, and I have to bring it back to her," Yamanaka said this week.

The boxers in the world title fight on Thursday's undercard both made weight. Junior featherweight world titleholder Ryosuke Iwasa, a 28-year-old Japanese southpaw, was 121.75 pounds for his first title defense, just under the 122-pound division limit. Challenger Ernesto Saulong, 28, of the Philippines, weighed 121.5 pounds.

Iwasa won his world title by sixth-round knockout of countryman Yukinori Oguni on Sept. 13.