The Japan Sambo Championships and Russian President's Cup have been postponed until July 25, when the Olympics are due to be underway, because of coronavirus concerns.
Japanese capital Tokyo is due to stage the sambo competition, but is currently under a state of emergency due to rising coronavirus case numbers.
Japan has now recorded more than 340,000 total cases and in excess of 4,600 deaths.
Tokyo Prefecture has reported more than 88,000 total cases - more than double any other.
Nobuyuki Asai, vice-president of the Japanese Sambo Federation and a senior tournament organiser, told Russia's state news agency TASS that July 25 had been chosen as the new date for the event, replacing February 7, due to he health situation.
"It is good that Tokyo will host the Russian President's Sambo Cup during the Olympic period, which is not an Olympic event," Asai is quoted as saying.
The 2021 edition of the tournament is set to be the ninth Russian President's Cup held in Japan, with the 2020 version attracting more than 100 athletes.
It will be the 47th staging of the Japan Sambo Championships.
July 25 is a Sunday and 3x3 basketball, archery, badminton, basketball, baseball and softball, beach volleyball, boxing, canoe slalom, diving, equestrian, road cycling, fencing, football, handball, hockey, judo, rowing, sailing, shooting, skateboarding, surfing, swimming, table tennis, taekwondo, volleyball, water polo and wrestling events are all scheduled to be taking place at the Tokyo 2020 Olympics.
Weightlifting, taekwondo, swimming, skateboarding, shooting, judo, fencing, diving and road cycling all have medal events scheduled on July 25.