Photo: Star of the show -- Zou Shiming of China

A starting field of 557 boxers from around the globe has been trimmed to 88 quarterfinalists, and Thursday's packed 44-bout schedule for 11 weight divisions will cut that surviving number in half at the AIBA World Boxing Championships Chicago 2007.

From here out, every winner will have to compete in the ring for three consecutive days. Eleven boxers who win all the way through will become world champions, decided in finals Saturday at the University of Illinois-Chicago's UIC Pavilion.

Key quarterfinal matchups Thursday will pit 2005 World Champion and 2004 Olympic bronze medalist Zou Shiming of China against Patrick Barnes of Ireland in a light flyweight matchup; and 2004 Olympic gold medalist Alexey Tishchenko of Russia against Pichai Sayota of Thailand in a lightweight bout.

Nine Russian and six American boxers will be in action, pitted against each other in four bouts, all seeking to advance to Friday's semifinals. Six Chinese boxers also reached the quarterfinals.