The charismatic and colourful Shingo Katayama of Japan is aiming to light up OneAsia's Thailand Open this week with the type of freewheeling play that has won him US$17.3 million in his homeland.

Katayama, who has swapped his trademark Stetson for a less flamboyant pork pie hat, is up against one of the strongest ever fields assembled for the US$1 million Thailand Open at Burapha Golf Club near Pattaya from August 26-29.

A sizable group of 56 Thai players, including recent winners Thaworn Wiratchant and Chawalit Plaphol, will challenge for the richest prize in tournament golf in The Kingdom alongside China's Liang Wenchong, who finished eighth in the PGA Championship at Whistling Straits, and last week's champion on the Mercedes-Benz Tour, Mardan Mamat of Singapore.

The US$1 million prize money is US$100,000 more than the combined total purse of the three Asian circuit events in Thailand this year.

Katayama, Japan's number one on five occasions and the winner of 26 events on the lucrative circuit, has been drawn with Chawalit and Mamat in a mouth-watering group.

Chawalit, who possesses one of the smoothest swings in Asian golf, is on the comeback trail after a couple of years in the doldrums and has won twice on the Mercedes-Benz Tour this season.

Mamat's play-off victory over Thailand's Pariya Junhasavasdikul in the Mercedes-Benz Masters Malaysia was made all the more remarkable as the Singaporean is fasting during Ramadan.

Another group that will be closely watched features Liang, winner of the season-opening Luxehills Chengdu Open on OneAsia, former Asian number one Thaworn and Kiwi Michael Hendry, the stylish champion of the Indonesia Open presented by Enjoy Jakarta.

Liang, second behind Hendry in the Indonesia Open, is just US$103,460 behind leader Y. E. Yang of Korea on the OneAsia Order of Merit and a victory this week will see him leapfrog the Volvo China Open winner into top spot.

"I am looking to win more events on OneAsia this season," said Liang, who shot a course record 64 in the third round of the PGA Championship, the final Major of the year. "I am currently number two on the Order of Merit and my target it to win the moneylist title this season."

Only two Thai players – Suthep Meesawat (1991) and Boonchu Ruangkit (1992 and 2004) – have won their home Open and Thaworn dearly wants the prize that has eluded him during a glittering career.

"I would love to win my home Open," said the 43-year-old Thaworn who has won 11 times on the Asian circuit. "It is the tournament every Thai player wants to win as we are playing for the King's Trophy."

"I have won before at Burapha Golf Club but from what I hear they are using a different layout this time. Still, I have good memories of the course."

Play starts on Thursday at 6.45am and the star players will be featured in the live television coverage on ESPN Star Sports from 1pm to 5pm Thai time.

This year's Thailand Open is being co-sponsored by Singha Corporation, PTT Public Company Limited, Thailand Convention & Exhibition Bureau (TCEB), Emirates, and CAT Telecom Public Company Limited.