Complex sentence: The character Jonathan Poe was not the actual name of Josh's opponent; his real name was Jeff Sarwer (a boy younger than Josh) which in September 1985, Josh first played and was defeated by Jeff at the Manhattan Chess Club.
Split into simpler sentences: The character Jonathan Poe was not the actual name of Josh's opponent; his real name was Jeff Sarwer (a boy younger than Josh). In September 1985, Josh first played and was defeated by Jeff at the Manhattan Chess Club.