By Chris Hogg
BBC News, Tokyo
An investigation is under way in Japan after allegations were made that the country's top sumo wrestler has been fixing matches.
A number of Sumo wrestlers have been questioned
Sumo's Grand Champion is a Mongolian called Asashoryu who won his 20th career title recently.
Asashoryu has not made any public comment about the claims.
The allegations come from an unnamed wrestler and another man said to be connected to the Grand Champion's training stable.
They claim, in a magazine article, that Asashoryu has been paying his opponents around $6,500 (£3,318) a match to let him win.
The Sumo Association has decided to investigate, questioning a number of wrestlers and Asashoryu's stable-master, all of whom have denied any wrong-doing.
Next week, sumo's bosses will discuss the claims with the six highest-ranking wrestlers, including the Grand Champion himself.
There have been allegations of match-fixing in sumo before.
It is not well paid until you reach the highest ranks, so an offer of several thousand dollars to throw a match might be tempting.
For an established wrestler, it might make sense to fix matches to help to retain his ranking, and the high salary and sponsorship opportunities that come with it.
It is possible, though, that the claims are motivated by something else.
Asashoryu is not Japanese. Some feel, rightly or wrongly, he has not worked as hard as other foreign wrestlers to adhere to the strict code of conduct of the sumo tradition and he dominates the sport.
Whatever the truth is here, sumo sets great store by loyalty and discipline, and many may be reluctant to speak to investigators as a matter of principle.
A few years ago, an academic study of corruption in the sport reported that two sumo wrestlers who made allegations of match-fixing died within hours of each other. They had dined together shortly before.
The report's authors expressed hope at the time that their deaths had been nothing more than purely coincidental.