In each round, exactly one half of participants is eliminated from the tournament. Therefore, the sequence of the numbers of survived participants and the number of matches in each round is this: round N of particicipants N of matches 1 512 == 2 3 4 5 6 7 8 = 2 (semifinal) 9 = 2 1 (final) -------------------------------------------------------------------------- Total (sum) = 511 matches.