What Is Nine Men's Morris?

Nine Men's Morris (also called Mills, Merels, or Morabaraba in some regions) is an abstract strategy board game for two players. Each player begins with nine pieces. The board consists of three concentric squares connected by lines at the midpoints of each side, creating 24 intersection points where pieces can be placed. The objective is to reduce your opponent to fewer than three pieces — or leave them with no legal move.

The game unfolds in two distinct phases. In the Placement Phase, players alternate placing one piece per turn on any empty intersection. In the Movement Phase, players slide pieces one step along a line to an adjacent empty intersection. Throughout both phases, the core tactic applies: align three pieces in a row along any line to form a mill — which lets you remove one of your opponent's pieces from the board.

The game plays in 10 to 20 minutes. It requires no reading, no arithmetic, and no equipment beyond the board and 18 pieces — which is likely why it has persisted for over three thousand years.

The Complete Rules of Nine Men's Morris

Setup

The board starts completely empty. One player takes nine black (or dark) pieces; the other takes nine white (or light) pieces. Decide who plays first — traditionally, the darker pieces go first. Players sit on opposite sides of the board.

Phase 1: Placement

Players alternate turns. On your turn, place one piece on any empty intersection on the board. Continue until all 18 pieces (nine per player) have been placed.

If at any point during placement you align three of your own pieces in a row along any straight line segment (a mill), you immediately remove one of your opponent's pieces from the board. Important rule: you cannot remove a piece that is part of your opponent's current mill, unless all of their remaining pieces are in mills.

Phase 2: Movement

Once all pieces are placed, the game enters the Movement Phase. On your turn, slide one of your pieces one step along a line to an adjacent empty intersection. You cannot jump over other pieces or move to a non-adjacent intersection (with one exception — see Flying below).

As in the Placement Phase, completing a mill during movement lets you immediately remove one opponent piece not in a mill.

The Mill (Three in a Row)

A mill is formed when three of your pieces occupy all three intersections along any straight line segment on the board. The board has 16 possible mill lines — four along each side of each of the three rings, plus four along the connecting spokes.

A key strategic technique is mill oscillation: moving a piece out of a mill on one turn and back in on the next, reforming the mill and earning a new capture every two turns. This is completely legal and is one of the game's most powerful winning techniques.

The Flying Rule

When a player is reduced to exactly three pieces, they gain the ability to fly: on their turn, they may move any of their pieces to any empty intersection on the board, not just adjacent ones. This rule gives a player with three pieces dramatically increased mobility and can completely change the game's momentum.

How to Win

You win by achieving either of these conditions:

Piece elimination: Your opponent has fewer than three pieces. With only two pieces, they cannot form a mill and the game is over.

No legal moves: Your opponent has pieces on the board, but every piece is completely surrounded by occupied intersections — they have no legal move available.

Nine Men's Morris Strategy: How to Win

Control the Spoke Midpoints in the Opening

The four nodes where the connecting lines (spokes) meet each ring are the most strategically valuable positions on the board. Each spoke midpoint belongs to three possible mills simultaneously — two along ring edges and one along the spoke. Compare this to corner intersections, which belong to only two possible mills. Claiming spoke midpoints in your first four placements gives you maximum mill-forming options throughout the game.

Try to claim at least two spoke midpoints in your first four placements. If your opponent lets you claim all four on one ring, you will have an overwhelming positional advantage.

Build Two Mill Threats Simultaneously

The most important strategic principle in Nine Men's Morris: one mill threat can be blocked, but two cannot. If you are threatening to complete a mill on the top of the board AND on the right side of the board simultaneously, your opponent can only move to one location — giving you a free capture from the other mill. These double-threat positions (called forks) are the primary mechanism by which winning positions are created.

Building a fork requires placing pieces at the intersection of two incomplete mill lines — one piece participating in both threats simultaneously. Spoke midpoints are the most common fork positions because they belong to both a ring-edge line and a spoke line.

Oscillate Your Mills for Consistent Captures

Once you have formed a mill, the most powerful use of it is oscillation: move one piece out of the mill on one turn (breaking it), then move it back on the next turn (reforming it). Each reformation earns a new capture. Done repeatedly, this gives you a free capture every two turns from a single formation — and there is often little your opponent can do about it unless they can form their own mill and capture one of your mill pieces.

The Flying Rule as an Offensive Weapon

When you are reduced to three pieces and gain flying ability, the instinct is to retreat to a safe corner. This is almost always wrong. Corners have only two adjacent intersections — they trap your pieces in restrictive positions. Instead, fly to a node that immediately threatens to complete a mill. Your three pieces, with full board access, can threaten mill completions from anywhere. Use flying to strike, not to hide.

Restrict Your Opponent's Mobility

The second win condition — no legal moves — is achievable by surrounding your opponent's pieces. Corner positions are most easily blocked because they have only two adjacent nodes. By positioning your pieces to deny your opponent's pieces any open adjacent node, you can win without needing to reduce them below three pieces. This strategy is most effective when you have a significant piece-count advantage.

Nine Men's Morris Variants

Six Men's Morris

Played with six pieces per player on a board with only the outer and middle rings (no inner ring). Six Men's Morris plays faster and is considered a good introduction for children before learning the full nine-piece game. There is no flying rule in most versions.

Twelve Men's Morris

Played with twelve pieces per player on the same three-ring board, but with additional diagonal connections at the corners — creating more mill lines and a more complex game. Twelve Men's Morris is the historical predecessor of what modern Ninestone calls the "Ninestone II" variant.

Morabaraba

The Southern African variant of Nine Men's Morris, widely played in South Africa, Lesotho, and Swaziland. Morabaraba uses cattle thematically and has some differences in rules around mill formation, but shares the same board structure and core mechanic. It has a competitive tradition with organized tournaments in several countries.

Ninestone

Ninestone is a modern adaptation of Nine Men's Morris created by Ed Armstrong in Maine in the 1980s and now available free online. The rules are essentially identical to Nine Men's Morris with a few clarifications: the three-in-a-row formation is called a Rail™ instead of a mill, the flying rule activates at exactly three pieces, and reforming a broken Rail™ always counts as a new capture. Ninestone also features a second variant (Ninestone II) with diagonal connections, equivalent to Twelve Men's Morris.

The History of Nine Men's Morris in Brief

The game's documented history stretches back at least 3,400 years. The oldest known boards are carved into the roofing slabs of an ancient Egyptian temple complex at Kurna, dated to approximately 1400 BCE. Similar boards appear in Roman archaeological sites across Britain and continental Europe, carved into legionary camp floors and military sites. The game was evidently a common pastime of Roman soldiers stationed across the empire.

By the medieval period, Nine Men's Morris was one of the most widely played games in Europe — referenced in Geoffrey Chaucer's writings and explicitly named in Shakespeare's A Midsummer Night's Dream (1600). The game was played at every level of society, from peasants scratching boards in village dirt to nobles with ornate wooden tablets.

The game declined in mainstream popularity during the 18th and 19th centuries but was never forgotten. In 1994, computer scientists at the University of Alberta computationally analyzed the game and proved it is a draw under perfect play — though achieving anything close to perfect play is far beyond human capability in practice. See our full history article for the complete story.

Where to Play Nine Men's Morris Online Free

The easiest way to play Nine Men's Morris online is through Ninestone, a free browser-based adaptation available at this site. No download, no account, no payment. Features include:

• Play against an AI opponent at Easy, Medium, or Hard difficulty
• Pass-and-play mode for two players on one device
• Standard Nine Men's Morris rules plus the Ninestone II diagonal variant
• Full rules enforcement — the game prevents illegal moves and applies the flying rule automatically
• Works on any modern device: desktop, tablet, or phone

The Hard AI provides a genuine challenge even for experienced players. It uses a depth-20 minimax search with a transposition table, killer move heuristics, and correct implementation of all rules including the capture restriction on mill pieces.