The July Grand Sumo Tournament opened on Sunday in the central Japanese city of Nagoya.
Yokozuna Grand Champion Hakuho returned to the ring after skipping the May tournament due to an injury.
The 34-year-old is aiming to clinch a 43rd career title to break his own record.
He beat up-and-coming Abi on the first day.
The other Yokozuna, Kakuryu, also started with a win against Ryuden.
Rank-and-filer Asanoyama is drawing much attention after winning the May tournament.
He beat Ozeki champion Goeido on Sunday.
Ozeki Takakeisho, who was promoted to the sport's second-highest rank in May, is sitting out the competition because of an injury.
He will be demoted after the tournament.