Two-time champion Peter Gade Christensen of Denmark lashed out at international badminton regulations after being forced to qualify for the main draw at the 180,000-dollar Japan Open on Tuesday.

The former world No. 1, who came back from knee surgery to win the US Open in September, trounced Thiraya Laohathaimongkol of Thailand 15-0, 15-0 and went on to beat Japan's Shinya Otsuka 15-10, 15-6 to make the main draw.

But Gade was irritated that he had been made to play preliminary rounds after his lengthy lay-off last year saw him slide in the rankings.

"It's a stupid rule," said Gade, who injured his right knee because of "too much practice".

"I knew when I was away with the injury, I had to play qualification in a lot of tournaments before I'm back. It should be a ranking safety security.

"I don't think as a sport we can afford to have good players playing qualifiying. Now I'm on my way back and I take one step at a time. I still need about 10 to 15 per cent to be on that level (when he was number one), but now I have a lot of motivation, I'm getting better and better," he said.

Winning back the title he won in 1998 and 1999 will be tough for Gade, who is likely to meet defending champion and Asian Games silver medallist Lee Hyun-Il of South Korea in the quarter-finals.

Former All-England champion Chen Hong is top seed, with fellow Chinese Xia Xuanze seeded two.

Chen is in the same half of the draw as 2001 Japan Open winner Muhammad Roslin Hashim of Malaysia, eighth seed Boonsak Polsana of Thailand, fourth seed Kenneth Jonassen of Denmark, fifth seed Ong Ewe Hock of Malaysia, and 2000 Asian junior champion Lin Dan of China, ninth seed.

In the bottom half with Xia are Lee, Thailand Open winner Ronald Susilo of Singapore, Roslin's younger brother Muhammad Hafiz Hashim, who upset Chen to win the All-England in February, Asian Games champion Taufik Hidayat of Indonesia, and European champion Peter Rasmussen of Denmark.

Chinese women are expected to dominate the women's singles with top seed Zhang Ning, world champion Gong Ruina, third seed, two-time defending champion Zhou Mi, fourth seed, and sixth seed Xie Xingfang leading the draw.

Challengers against them are former China national team player Wang Chen, seeded second; 1997 Japan Open winner Mia Audina of The Netherlands, the seventh seed; the 1998 Asian Games champion Kanako Yonekura of Japan, the fifth seed; and 1999 world champion Camilla Martin of Denmark, who is seeded eighth.