Kento Momota, only restored to the national team in January after a suspension for illegal gambling, became the first Japanese man to win a badminton singles world championship on Sunday.
Earlier, Mayu Matsumoto and Wakana Nagahara came from behind to win an all-Japanese women's doubles championship final, defeating compatriots Yuki Fukushima and Sayaka Hirota. Japan completed a record six-medal haul with Takeshi Kamura and Keigo Sonoda settling for silver in the men's doubles final.
The 23-year-old Momota, the first Japanese to medal in singles at the badminton worlds when he won a bronze in 2015, missed the 2016 Olympics due to a suspension for gambling at a casino, which are illegal in Japan.