Your question's answer is written in Go rules : Since the black player starts the game, he has a significant advantage. In order to balance it, a value called komi is subtracted from the black player score. It is 5.5 for a 19x19 board, 4.5 for a 13x13 board and 3.5 for a 9x9 board.
(esconder) Se, de repente, o site aparecer numa língua diferente, basta clicar na bandeira da sua língua e tudo voltará ao normal. (pauloaguia) (mostrar todas as dicas)