Strategy
Nine Men’s Morris
Line up three pieces to form a mill and capture.
The great classic with nine pieces: place them, move them, then fly when only three are left. Every mill you form removes an opposing piece.
- Players
- 1 or 2 players
- Length
- 15 min
- Against the AI
- Two players on one device
15 days of full access, no account · No download
How to play
Goal
Reduce your opponent to two pieces, or block them so they can no longer move.
How it works
- Placing: each player has nine pieces and places them in turn on a free point. White starts.
- Moving: once all the pieces are placed, you slide a piece along a line to a free neighbouring point.
- Flying: a player reduced to three pieces may jump to any free point.
- Mill: three pieces of your colour in a row on the same line. Forming a mill lets you remove an opposing piece, but not a piece that is part of a mill, unless all of the opponent’s pieces are in mills.
- You can open a mill and close it again on the next turn to capture again.
- A player who is blocked, or reduced to two pieces, loses the game. A position repeated three times is a draw, as are fifty moves by each side without any capture.
- Play by tapping a point, or drag a piece to its destination.
Tip: the “running” mill, where a piece shuttles back and forth between two mills, captures on every turn. During the placing phase, keep some mobility and avoid locking yourself in.
About the AI
Negamax search with alpha-beta and a null window on a bitboard representation of the board, with iterative deepening, a Zobrist transposition table, killer moves and repetition detection. The evaluation weighs material, mills formed and threatened, running mills and mobility. The lower levels reduce the depth and add inaccuracies.
AI levels
- BeginnerSees its own immediate mills, rarely yours.
- AmateurBlocks simple threats and lets chances slip by.
- IntermediateCalculates three plies and rarely errs.
- ExpertSeven plies ahead: you need a real strategy to beat it.
- MasterDeep search within a time limit: nearly unbeatable.
