Malaysia's top seed Lee Chong Wei moved into the second round of the Badminton World Federation (BWF) Japan Super Series as the main draw began play at the Tokyo Metropolitan Gymnasium.
The four-time winner of the tournament, who won his third consecutive Olympic silver medal at Rio 2016 last month, eased through against Thailand's Boonsak Ponsana, 21-14, 21-13.
There was also progression for Denmark's second and third seeds in the men's singles, Viktor Axelsen and Jan Ø. Jørgensen respectively.
Axelsen, the European champion and Rio 2016 Olympic bronze medallist, got the better of Hong Kong's Wong Wing Ki, 21-16, 21-11.
Jørgensen's passage was sealed after he beat Japanese qualifier Riichi Takeshita, 21-15, 21-13.
Fourth seed Tian Houwei of China was a surprise exit, however, as he was ousted in three by Chinese Taipei's Hsu Jen-hao.
Tian, the bronze medallist at this year's Asian Championships in Wuhan, was beaten 17-21, 21-14, 21-12 by his opponent who condemned him to an early exit.
In the women's competition, Spain's top seed and Olympic champion Carolina Marin has withdrawn, meaning home player Nozomi Okuhara, the defending champion, is the best ranked player at the event.
The Olympic bronze medallist eased past Denmark's Line Kjærsfeldt 21-13, 21-16 to reach round two.
Also through is third seed Ratchanok Intanon of Thailand who got the better of Pai Yu-po of Chinese Taipei, 21-16, 21-12.
As with the men's draw, the fourth seed exited the competition as Tai Tzu-ying fell to defeat.
The Chinese Taipei player lost to Japan's Sayaka Sato, 22-20, 21-14.
The competition, the seventh Super Series event of the season, will continue tomorrow in the Japanese capital, the host city of the 2020 Summer Olympics and Paralympics.