  What is the physical origin of player cooperation in minority game? And how
to obtain maximum global wealth in minority game? We answer the above questions
by studying a variant of minority game from which players choose among $N_c$
alternatives according to strategies picked from a restricted set of strategy
space. Our numerical experiment concludes that player cooperation is the result
of a suitable size of sampling in the available strategy space. Hence, the
overall performance of the game can be improved by suitably adjusting the
strategy space size.
