To provide a method and tools for a new board game in which 2-6 players can participate.

This board game is constituted of a polygonal board 2 comprising systematically combined plural equilateral triangle through holes 1 and 6 kinds of different colored equilateral triangle pieces 3-8 to be fit therein, and 2-6 players are to fit the pieces 3-8 into the through holes in a prescribed order. The following is set as the rule: when one of those pieces 3-8 is to be fit in, at least one side of a piece to be fit then must be in touch with one side of an already fit piece, and an opponent piece sandwiched by own pieces in 6 directions parallel to one side of pieces 3-8 can be substituted by an own piece and, at that time, player's own piece is fit into the through hole from upside to push out the opponent' s piece.