Osaka, 21, spoke to NHK (h/t BBC Sport) and confirmed she has begun proceedings to opt for Japanese citizenship: "It is a special feeling to aim for the Olympics as a representative of Japan. I think that playing with the pride of the country will make me feel more emotional."
The two-time major champion was born in Osaka, Japan, but moved to the United States when she was three. Her mother, Tamaki, is Japanese, while her father and coach, Leonard Francois, is from Haiti.
Per ESPN, dual-nationality citizen Osaka will be obliged under Japanese law to select one when she turns 22 on Wednesday, October 16.
Osaka already represents Japan in the Fed Cup and on the WTA Tour, and her decision to play for her birth nation in a home Olympics shouldn't come as much of a surprise.
Japan has never won a gold medal in tennis at the Olympics. It has two silvers and one bronze, but Osaka's first appearance at a Summer Games presents arguably its best chance of making the top step of the medal podium next year.
Osaka is enjoying a strong run of form and recently followed up victory at the 2019 Pan Pacific Open by beating Ashleigh Barty 3-6, 6-3, 6-2 to win the 2019 China Open:
Men's star Kei Nishikori would be considered Japan's other genuine contender for Olympic gold, though a runner-up finish at the 2014 U.S. Open remains as close as he's come to winning a Grand Slam.
Osaka became the first Japanese player to win a major when she defeated Serena Williams in the 2018 U.S. Open final, and she'll hope to write more history in honour of her country in Tokyo.