Tokyo - Floyd Mayweather's match against a Japanese kickboxer is once again on for New Year's Eve as an exhibition fight with knockouts allowed but likely no decision granted on a win or a loss.

Nobuyuki Sakakibara, the head of Rizin Fighting Federation, which is putting on the three-round exhibition, told reporters Saturday at Tokyo's Haneda airport that "a misunderstanding" was behind Mayweather, 41, appearing to back out.

The event, to be held at Saitama Super Arena in suburban Tokyo on December 31, was initially announced earlier this month.

Sakakibara, who just returned holding meetings with Mayweather in Los Angeles, said the basic agreement had not changed from the initial contract, which did not allow kicking.

He said Tenshin Nasukawa, 20, will have a chance to knock out Mayweather, but the results will not go against either fighter's win-loss record. Other details are still being worked out.

"We don't want people to think this is some half-hearted playing around," Sakakibara said, appearing before reporters in a sweatshirt.

He also said spectators would not see mere "casual sparring."

Sakakibara stressed the event would include the largest payout for an exhibition fight but did not give specifics. Mayweather previously said he was already making "seven figures" just by talking about it.

"He will stand before Tenshin December 31," Sakakibara said of Mayweather.

"It's up to Tenshin whether he can create a miracle."

Sakakibara acknowledged he could not rule out a last-minute cancellation but promised he would do his best to make what he called the "fun show" happen. He also said he could not tell what kind of shape Mayweather was in because he has not watched him work out.

The promoter compared the event to the first "Rocky" film, as well as to the 1976 match between Muhammad Ali and Japanese wrestler Antonio Inoki.

Mayweather told TMZ Sports earlier this week he would take part in the exhibition match after all, stressing he was making "a ton of money" even in retirement.

The best seats for the fight will cost 100 000 yen ($900) each. The cheapest seats cost 7 000 yen ($60).