Sumo tournaments are held every January , May , and September at this arena ( KOKUGIKAN SUMO STADIUM ).

The new KOKUGIKAN was built in 1985 to return the tournaments to the historic Ryogoku location after a time in Kurumae.

The stadium houses the Grand Sumo Hall of Fame and Museum ( free admittance , except when tournaments in session ).

The rainwater is collected in a tank placed at the basement to use in the facility .