How to play
Twelve Men’s Morris uses the familiar mill board of three nested squares, then adds four diagonals. Each diagonal runs from a corner of the outer square through the matching corner of the middle square to the inner one. The board still has 24 points, but it now holds 20 lines of three instead of 16, and every corner sits on three lines. Each player gets twelve pieces. White moves first; against the computer, that’s you.
The rules run the same way as the nine-piece game, so here is the short version.
- Place. Take turns putting a piece from your hand on any empty point.
- Slide. With your hand empty, move one piece per turn to a neighbouring empty point along a line, and the diagonals count as lines.
- Fly. With exactly three pieces left, you may move a piece to any empty point.
- Capture. Close a mill (three in a line, diagonals included) and remove one enemy piece. Pieces in a mill are safe unless every enemy piece is in one.
- Win. Your opponent loses when they are down to two pieces, counting the ones in hand, or when they can’t move on their turn.
The full-board draw
This is the rule that makes the twelve-piece game feel different. Twelve plus twelve is 24, exactly the number of points. If all pieces go down without a single mill being made, the board is full, nobody can slide anywhere, and the game ends as a draw before the moving stage even begins.
In practice, mills during placement are hard to avoid on this board. Twenty lines over 24 points means almost every placement creates or blocks some threat, so the placing stage plays like a tense game of noughts and crosses with captures. Each capture opens a point, and those few holes decide how the sliding stage goes.
A second draw rule is shared with the smaller game: 50 moves on each side with no capture ends the game level.
Controls
Tap an empty point to put a piece there. When sliding, tap one of your pieces, then the destination. After you close a mill, the pieces you may take are highlighted; tap one to remove it. The status line shows how many pieces each side still has in total, and the last move is marked on the board.
Choose your Opponent at the top: Computer (with Easy, Medium and Hard) or Friend, for two people taking turns on one device. Hint briefly marks a sensible move, Undo steps back (one move against a friend, your move plus the reply against the computer), and New game starts over. Progress and settings are saved automatically.
Strategy
Treat the corners as prime points. On the plain board a corner is the weakest spot, with two neighbours. Here the diagonals give every corner a third line. The middle-square corners are especially strong: the diagonal passes through them, so they get four neighbours (two along the square, one outward, one inward), as many as the best junction points.
Expect captures early. With this many lines, letting your opponent hold two open threats at once costs a piece almost every time. Check the diagonals before every placement; it’s the threat new players miss most.
Think about the draw before it happens. If you’re ahead in position, push for a mill while placing, because a full board throws your advantage away. If the computer is outplaying you, a quiet placement that blocks everything and fills the last points can save a draw.
Plan for a crowded slide. After placement only a handful of points are empty. Blockade wins far more often than in the nine-piece game: a side whose pieces are all boxed in loses immediately. Before your last placements, check which of your pieces will have an empty neighbour.
Running mills still decide endgames. One piece swinging between two mills captures every other turn. The diagonals give you more places to build this shape, and your opponent more places to break it.
New to mills? Start with Nine Men’s Morris, the same board without diagonals and with three fewer pieces per side. Players in southern Africa know a close relative, Morabaraba, which also uses twelve pieces and diagonal lines.
If you enjoy Twelve Men’s Morris, try Twist Five or Ultimate Tic-Tac-Toe next.
