How to play

Players take turns placing a stone on any empty square, black first. The first player to make an unbroken line of five stones of their color, across, down or diagonally, wins. A line longer than five also counts. If the board fills up with no five, it is a draw. This game is known as Gomoku in Japan and has many local names. Choose a 9 × 9 board for a quick game, or 13 × 13 for a longer one with more room for plans.

Against the computer there are three levels. Easy mostly attacks and sometimes plays a random square. Medium balances building its own lines with blocking yours. Hard also looks at your best reply to each of its top moves. Or pick 2 players to share one screen. The last stone played has a colored ring.

Tips

Black moves first and has an advantage, so the second player has to defend carefully. A row of four stones with both ends open (an “open four”) can’t be stopped, because there are two squares that complete it, so block an open three before it becomes an open four. The strongest plans create two threats at once, for example a three in one direction and another three crossing it. Keep your stones connected near the center, and don’t forget to check the diagonals.