The fourth seed is in fine form after winning the Indonesia Open on Sunday (July 21) and made short work of Russia's Evgeniya Kosetskaya at the Musashino Forest Sports Plaza venue which will host Olympic competition next year.

Yamaguchi, who won World Championship bronze last year, came through against the qualifier 21-9, 21-9.

Today saw the bottom half of both the men's and women's draw contest their first round matches.

No seeds fell among the women as China's second-ranked Chen Yufei eased past Indonesia's Fitriani 21-5, 21-19.

India's fifth seed PV Sindhu, beaten in the Indonesia final by Yamaguchi, got past China's Han Yue 21-9, 21-17.

There was also more Japanese success as Aya Ohori won an all unseeded duel with Scotland's Kirsty Gilmour, 21-18, 21-19.

In the men's event, eighth seed Srikanth Kidambi was knocked out by his Indian team-mate Prannoy Kumar, 13-21, 21-11, 22-20.

China's Beijing 2008 and London 2012 Olympic champion Lin Dan, who is not seeded, was also beaten in three as Denmark's Jan Ø. Jørgensen prevailed 16-21, 21-11, 23-21.

Chinese Taipei's fourth seed and Indonesia winner Chou Tien-chen knocked out South Korea's Lee Dong-keun 21-17, 21-12.

Second round matches will take place tomorrow at an event rated at Super 750 on the BWF World Tour, the second highest level.

All of the Olympic test events are being held under the "Ready Steady Tokyo" banner with competitions in weightlifting, archery, surfing and road cycling having taken place so far.

The badminton will conclude on Sunday (July 28) with finals across the singles and doubles events. 

Men's second seed Shi Yuqi of China and third seed Viktor Axelsen of Denmark have both withdrawn through injury.