Akane Yamaguchi, the sixth seed, lost to seventh seeded opponent Sun Yu 21-17, 21-18 in the Japanese capital. 

There was then further disappointment for Japan as qualifier Aya Ohori was defeated by China's eighth seed He Bingjiao, 21-17, 22-20.

In the men's tournament, triple Olympic silver medallist Lee Chong Wei reached the final and has still not dropped a game at the tournament.

The Malaysian top seed, a three-time winner of the event, knocked out Germany's Marc Zwiebler 21-14, 21-15.

His reward in the final will be a contest with Denmark's Jan Ø. Jørgensen, the third seed, who succeeded where compatriot Viktor Axelsen failed by getting past Son Wan-ho.

Axelsen, the second seed and Rio 2016 Olympic bronze medallist, was beaten by the South Korean in the quarter-finals but Jørgensen had no such problems, coming through 21-14, 21-19.

Both finals are due to be played tomorrow in the 2020 Olympic host city, with the doubles competitions also reaching their conclusion.

The men's doubles final will pit Kim Gi-jung and Ko Sung-hyun of South Korea against China's Li Junhui and Liu Yuchen, the seventh and eighth seeds respectively.

In the women's competition there is hope for home gold as Japan's top seeds Misaki Matsutomo and Ayaka Takahashi will take on Denmark's second ranked team Christinna Pedersen and Kamilla Rytter Juhl.

The mixed doubles final will pit South Korea's top seeds Ko and Kim Ha-na against China's Zheng Siwei and Chen Qingchen.