Hakuho on Friday pulled out of the Autumn Grand Sumo Tournament getting under way Sunday due to pain in his left knee, becoming the third yokozuna to withdraw from the meet after Kisenosato and Kakuryu.
Based on official records kept by the Japan Sumo Association since the Showa era (1926-1989), it is the first time for three grand champions to miss the opening day of a tourney.
Harumafuji is now the only yokozuna set to compete on the first day of the 15-day meet at Ryogoku Kokugikan in Tokyo.
Hakuho, who was seeking his third straight Emperor's Cup and an unprecedented 40th title overall, will sit out a tourney for the first time since the March basho in Osaka where he pulled out on the fifth day due to injuries to his right toe and thigh, and sixth time in all.
The 32-year-old Mongolian also missed part or all of the Autumn tourney the past two years.
"I think (Hakuho) felt until the last minute that he wanted to compete but his knee was not healed," his stablemaster Miyagino said. "He shouldn't strain himself and perform poor sumo. We have no choice but to have him recover promptly."
At the previous meet two months ago in Nagoya, Hakuho captured a record 39th career title while surpassing the late former yokozuna Chiyonofuji and former ozeki Kaio to climb atop the all-time bout wins list with 1,050 career wins.
The sumo world got four yokozuna for the first time in 17 years at the Spring tourney in March, but there have not been any meet since in which all four lasted the entire duration.