TOKYO, Japan – For the first time since it began televising sumo tournaments 57 years ago, Japan’s public broadcasting network decided yesterday not to air the upcoming competition live because of a gambling scandal that has sullied the sport’s reputation.

The decision underscored anger among the ancient sport’s fans over the behavior of coaches and wrestlers who are accused of gambling heavily on baseball, sometimes with gangsters as middlemen.

NHK, which has broadcast each of the six annual tournaments since 1953, said the scandal generated a flood of complaints from viewers, with most saying that they did not want the 15-day competition that begins on Sunday to be aired.

Instead of its usual live broadcasts of the top divisions, NHK will show a delayed, abbreviated version, the network said on its website.

The scandal has captured Japanese headlines and topped news broadcasts for weeks.

After much public hand wringing, the Japan Sumo Association on Sunday banned senior wrestler Kotomitsuki and his coach, Otake, and its chairman agreed to temporarily step down. But many see the actions as not going far enough to restore sumo’s tarnished image.

“We would like all of you to stake your life on this and make a fresh start,” Education Minister Fumio Kawabata told the association’s acting chief on Tuesday before the NHK announcement. He said this could be sumo’s last chance to regain face.

Responding to allegations in weekly magazines, the 34-year-old Kotomitsuki, who holds the sport’s second-highest rank, revealed last month he bet on professional baseball. Otake, who is a former wrestler, acknowledged running up betting debts of more than $50,000.

An internal survey by the JSA last month found at least 65 of its members had been involved in illegal gambling. Police are currently investigating the allegations, and one arrest has been made.

Though still widely popular, sumo is not the draw it used to be.

NHK, which has also broadcast the tournaments on radio since 1928, is the only major network that airs the tournaments live. Commercial networks used to have the tournaments in their schedules, but pulled them as ratings slid and the sumo authorities requested more money for broadcasting rights.

The sport has also been hamstrung by several scandals in recent years and is attracting fewer Japanese wrestlers good enough to make the top ranks. The sport’s reigning grand champion, Hakuho — who is not implicated in the gambling scandal — is Mongolian, and most of the best wrestlers are also foreigners.

Because of the sport’s origins as a religious ritual, the ring is considered sacred ground and wrestlers are held to stringent standards of behavior and ethics.

But breaches of those standards had become more common.

Top wrestler Asashoryu of Mongolia recently quit in disgrace after media reports that he got in a drunken fight outside a bar. The sport has also been involved in criminal investigations into the death of a wrestler who was brutally hazed and into the use of marijuana by top-division wrestlers.

The current scandal also deepened concerns that the sport has closer ties to gangsters than officials are willing to admit.

Allegations of bout-fixing at the behest of gangsters have been frequently raised in Japan’s tabloid media, but the sumo association has repeatedly denied that.

In May, two sumo coaches were demoted for providing ringside seats to members of a notorious crime syndicate.