Gomoku

Connect exactly 5 of the same stones in a row (horizontally, vertically or diagonally).

Put your piece on any unoccupied spot of the board. Try to make a line of 5 pieces in a row, either horizontally, up and down, or at an angle. Stop your opponent from completing their own row of five. Alternate setting pieces with your rival until one participant wins in making a line of 5. Note that the contest ends immediately when a line of five is made, with no need to cover the entire board.