Gomoku: five stones in a row

Gomoku: Five Stones in a Row is a board logic game for two players. On a square board measuring 19×19 (in the traditional version) or 15×15 (in the modern sports version) points, players alternately place stones of two colors. The winner is the one who is the first to build a continuous row of five stones of his color vertically, horizontally or diagonally. It has many options, differing in individual details of the rules. The game is believed to have been invented in China more than two thousand years ago. Currently, the game is known all over the world; sporting competitions are held based on it.