In the Paralympics, football five-a-side has started its preliminary round, with Japan beating France 4-0 in the first match.
In the sport, each team has four outfield players with visual impairments, and a goalkeeper who can be fully or partially sighted.
Eight teams are participating. As host nation, Japan was awarded a slot in the sport for the first time.
On Monday, Japan will play against Brazil, which has won the gold in the past four Games.
Brazil won against China in its first match.
Meanwhile, Japanese athlete Tani Mami said she had regrets about coming in 10th in the triathlon.
When Tokyo won its bid to host the Games in 2013, she made a speech at the IOC's general meeting about how sports encouraged her after she lost a leg and her hometown was hit by the earthquake and tsunami in 2011. Now she says that eight years later, she is so happy to be able to participate.