What You Need to Play

Nine Men's Morris requires a game board and 18 playing pieces — nine in one color (traditionally dark) and nine in another (traditionally light). The board consists of three concentric squares, each with eight intersection points at the corners and midpoints of each side. The midpoints of corresponding sides are connected by lines (spokes) crossing all three squares, creating 24 total intersection points where pieces can be placed.

If you don't have a physical set, you can play the online adaptation Ninestone free in your browser — no download or account required. The digital version handles all rule enforcement automatically.

Setup

The board starts completely empty. One player takes nine dark pieces; the other takes nine light pieces. By convention, the player with dark pieces moves first. No other setup is required — pieces are placed from a reserve rather than starting on the board.

Phase 1: Placement

The game begins with the Placement Phase. Players alternate turns, and on each turn, the active player places one piece from their reserve onto any empty intersection on the board. This continues until all 18 pieces have been placed — nine turns each.

There are no restrictions on where you may place a piece during the Placement Phase — any empty intersection is legal. You do not have to place adjacent to existing pieces.

If at any point during placement you form a mill (see below), you immediately remove one of your opponent's pieces from the board before your opponent's next turn. The removed piece is eliminated from the game permanently.

What Is a Mill?

A mill is formed when you have three of your own pieces on all three intersections of any straight line segment on the board. Line segments include: any of the four sides of each ring (giving 12 ring-edge segments) and any of the four spokes connecting corresponding midpoints across all three rings (giving 4 spoke segments). The total is 16 possible mill lines on the standard board.

A mill is formed the moment the third piece is placed or moved into position. It is also formed when a piece moves back into a previously broken mill — this counts as a new mill and triggers a new capture.

The Capture Restriction

When you form a mill, you must remove one of your opponent's pieces from the board. However: you cannot remove a piece that is currently part of your opponent's active mill — unless all of your opponent's pieces are in mills, in which case you may remove from a mill. This rule protects established formations and is one of the most frequently misapplied rules for new players.

Phase 2: Movement

Once all 18 pieces have been placed, the game transitions to the Movement Phase. On each turn, the active player slides one of their pieces one step along a line to an adjacent empty intersection. Pieces may not jump over other pieces. Pieces may not move to a non-adjacent intersection (with the Flying Rule exception described below).

As during placement: if a move results in a mill being formed, the player who formed it immediately removes one opponent piece (not from a mill, unless all opponent pieces are in mills).

A player cannot pass their turn. If a player has pieces on the board but no legal moves (every piece is completely surrounded by occupied intersections), they lose the game immediately.

Mill Reformation: A Critical Rule

Moving a piece out of a mill does not prevent that mill from counting again later. If you later move a piece back into that same line to re-form the same three-in-a-row, it counts as a newly formed mill and triggers another capture. This rule enables the powerful oscillation technique: alternately moving a piece out of and back into a mill to earn a capture every two turns.

Some players mistakenly believe that a mill can only be "used once." This is incorrect in standard Nine Men's Morris rules. Every time the three-piece alignment is newly completed, a capture is earned.

The Flying Rule

When a player is reduced to exactly three pieces on the board, they gain a special ability: on their turn, they may move any of their pieces to any empty intersection on the board — not just adjacent ones. This is called Flying or the Fly Rule.

Flying activates at exactly three pieces. A player with four or more pieces must move to an adjacent intersection regardless of how constrained their position feels. The Flying Rule can dramatically shift game momentum: a player who seemed hopelessly cornered can suddenly threaten mills anywhere on the board.

How to Win

There are two ways to win at Nine Men's Morris:

Reduce your opponent to two pieces. A player with fewer than three pieces cannot form a mill. When a player is reduced below three (to two or one), the game ends and the other player wins.

Leave your opponent with no legal move. If a player has pieces on the board but cannot move any of them (every piece is surrounded on all sides by occupied intersections), they lose immediately. This win condition is rarer but can be deliberately engineered.

Regional Variations

Nine Men's Morris has been played for over 3,000 years across dozens of cultures, and regional variations exist. The most common variations concern:

The Flying Rule threshold: Some versions activate flying at three pieces; others do not have a flying rule at all. The three-piece threshold is the most common modern standard.

Mill reformation: Some regional variants do not allow the same mill to be re-formed for another capture. The standard modern rule — and the rule used in Ninestone — is that reformation always counts as a new mill.

Diagonal connections: Some historical variants add diagonal connections at the corners, creating additional mill lines. This is the basis of the Ninestone II variant and historical Twelve Men's Morris.

For competitive or tournament play, agree on all variant rules before the game begins. The rules described on this page represent the widely-accepted modern standard.

Quick Reference: Key Rules