The Japan Sumo Association has decided to have all its members, including wrestlers and stablemasters, tested for coronavirus infection.
The decision comes after Yokozuna Grand Champion Hakuho was confirmed to be infected on Tuesday and infection clusters occurred in some stables from December.
The association's public affairs director, Shibatayama, announced on Thursday that all members will take PCR tests before the New Year tournament begins on Sunday.
They are to be tested using kits provided to their stables on Thursday. All results should be known on Friday.
Shibatayama said the association decided to take the measure as it is most important to secure the safety of fans who come to the tournament.