Simplify the following text for a Grade 10 native English-speaking person.
Original: He had numerous strong results in the knockout tournaments for the FIDE World Chess Championships 1998-2004 , with his best result being a semi-finalist in 1997 .
Simplified: He had numerous strong results in the knockout tournaments for the FIDE Championships 1998 -- 2004 , with his best result being a semi-finalist in 1997 .