THE retirement of Tony Choi Yuk-kwan from international competition has taken the depth out of a Hong Kong team who are expecting a tough time at the expanded World Championships in Karachi, Pakistan next month. The event will feature 28 teams, four more than the previous maximum number of entries, and Hong Kong are in Pool E. Only countries in Pools A and B will be battling for the title and Hong Kong must top their three-team group, which also includes Argentina and Malaysia, to go into the play-offs for 13th to 20th positions. Leading the territory's challenge will be Faheem Khan, ranked 30th in the world, and Andrew Shum Siu-chung. The other members of the squad have yet to be named. With Choi, the 1990 Hong Kong champion, stepping down from selection, the other two places will be contested by Jackie Lee Chun-kit, Sunny Poon Yat-sing, Yang Man-sum, Wong Wai-hang and Dick Leung Kan-fai. Coach Chris Clark said: ''Tony will be sadly missed and we'll have to try out the younger players at number three. ''We have a banker at number one in Faheem, so everything depends on the twos and threes. ''I'm confident we can scrape past Argentina, although it will not be easy. Malaysia will be the tough one.'' If Hong Kong top the preliminary pool they will meet either Austria or Denmark, the likely candidates to finish fourth in Pool D. Otherwise they will go into the play-offs for 21st to 28th places.