-- Japanese swimmer Kosuke Kitajima on Monday vigorously defended charges by an American swimmer that he used an illegal kicking style to win a gold medal in the 100-meter breaststroke here Sunday night.

Kitajima conceded that he knows of no one else who uses his kicking method, but said in his 17 years of competition he has never once been warned that it was illegal.

"I was a little bit shocked when that kind of question [was] raised to me," Kitajima said through an interpreter to a small group of American reporters. "It was the last thing I was expecting. It was disappointing."

Kitajima beat world record-holder Brendan Hansen of the United States on Sunday night. He was responding to claims by U.S. backstroker Aaron Peirsol, a teammate of Hansen's at the University of Texas, who said he was infuriated because he felt Kitajima used a "dolphin kick" rather than the required breaststroke kick in the race.

Peirsol said he considered the tactic -- which the U.S. did not officially protest -- "cheating," and that the gold should belong to Hansen. Peirsol, who won the gold medal in the 100-meter backstroke Monday night, didn't back away from his comments afterward.

"At the Olympic level, only fair play should come out on top," Peirsol said. "There should be no shortcuts. . . . Just because it wasn't called doesn't mean it's right. And just because someone got away with something doesn't mean it was right."

Peirsol said American swimmers noticed Kitajima's technique at the 2003 World Championships in Barcelona, where he won both the 100 and 200 breaststrokes, and that swimmers at NCAA meets were routinely disqualified for using the same tactic. Peirsol did not clarify why, if that was the case, Americans didn't bring the matter to officials' attention sooner.

Kitajima said he specifically aimed to improve his kicking after finishing fourth in the 100 breaststroke at the 2000 Sydney Olympics. He said officials at the Barcelona meet confirmed to him that his style was legal.

"If I had swam illegally, I could be cautioned or sanctioned, but it never happened to me so far," he said. "After the race, I was not cautioned and was not sanctioned, and that shows how my technique is not under consideration of sanction or caution."

Kitajima's achievement was met with banner headlines in Japanese newspapers, where Peirsol's remarks were not mentioned, according to Hireshi Takeuchi, spokesman for the Japanese swim team who served as the interpreter during the interview.

The 22-year-old native of Tokyo still must compete in the 200-meter breaststroke, where he will once again find Hansen as his chief competition. Kitajima said he was pushed by Hansen's world record performance in July at the U.S. trials. But he said the questions raised by Peirsol slightly dampened his spirits, even after winning the gold medal.

"I have no idea why they raised the questions," Kitajima said. "That question got me slightly angry, but I don't mind. I don't take them seriously."