Nine Men’s Morris Rules, Explained

A note before the rules: you can play Nine Men’s Morris on this site. Start a game and choose Nine Men’s Morris as your board, or pick it in the online lobby. The site’s own game is Morabaraba, which English-language references call Twelve Men’s Morris. Everything below is the nine-piece game as it is commonly played; rules vary a little from place to place, so agree on them before you start.

The board

The board is three squares, one inside the other, with a line joining the midpoints of each side. That gives 24 points where pieces can stand. There are no diagonal lines. Each side of each square is a line of three points, and so is each of the four lines joining the squares, so there are 16 possible mills.

Each player has nine pieces of their own colour. The players agree who starts, and the board begins empty.

Phase one: placing

Players take turns placing one piece on any empty point. Three of your pieces in a straight line along one of the board’s lines is a mill. The moment you make a mill, you remove one of your opponent’s pieces from the board. It is out of the game for good.

You may not take a piece that is part of one of your opponent’s mills, unless every piece they have is in a mill. Placing continues until both players have put down all nine pieces, less any that were captured.

Phase two: moving

Once all pieces are placed, players take turns moving one of their pieces along a line to a neighbouring empty point. Pieces cannot jump. A move that completes a line of three is a new mill and removes a piece, just as in placing. Moving a piece out of a mill and back again on a later turn makes the mill again.

Phase three: flying

When a player is down to three pieces, many rule sets let that player fly: move a piece to any empty point on the board, not only a neighbouring one. It gives the weaker side a last chance to make mills. Some rule sets do without flying, so agree before you start.

How to win

You win when your opponent:

• is down to two pieces, and so can never make a mill again, or
• has no legal move on their turn, because every piece they have is blocked in.

Rules that vary

Players disagree on a few details, and it is worth settling them first:

• whether flying is allowed at three pieces;
• whether closing two mills with one move removes one piece or two;
• how to call a draw when neither player can make progress.

On this site a player with three pieces flies, a move that closes two mills removes one piece, and a game is drawn when the same position comes up a third time with the same player to move, or after 25 moves each without a capture.

How Nine Men’s Morris compares with Morabaraba

Morabaraba, played in South Africa, Lesotho and Botswana, uses the same board with four diagonal lines added through the corners and gives each player twelve pieces, called cows. The phases, mills and flying work the same way. The full breakdown is in Morabaraba vs Nine Men’s Morris, and the Morabaraba rules are short if you want to play it here.