In the game G0 two players alternate removing positive numbers of counters from a single pile and the winner is the player who removes the last counter. On the first move of the game, the player moving first can remove a maximum of k counters, k being specified in advance. On each subsequent move, a player can remove a maximum of f(n, t) counters where t was the number of counters removed by his opponent on the preceding move and n is the preceding pile size, where f : N