# Help For Nine Mens' Morris (NMM)

## Introduction

Welcome to the network Nine Mens' Morris (NMM) server. The rules of Nine Mens' Morris are below. The commands are the same for all pbmserv games.

Nine Mens' Morris is known by many names, including Merrills and Mühle. There may be other variations on the rules, but according to my information, these are the rules used by the World Merrills Association for the World Championships and by the Welt-Mühlespiel-Dachverband for the European Championships. More information can be found at Cliff Hamer's Merrills Page.

## Rules of Nine Mens' Morris (NMM)

Nine Mens' Morris is a game for two people, played on a special board with nine pieces, pegs or counters each.

The board has three 'concentric' squares linked at the mid points of their sides. This provides 24 intersecting points arranged in 16 lines of three.

A   B   C   D   E   F   G

1   +-----------+-----------+
|           |           |
2   |   +-------+-------+   |
|   |       |       |   |
3   |   |   +---+---+   |   |
|   |   |       |   |   |
4   +---+---+       +---+---+
|   |   |       |   |   |
5   |   |   +---+---+   |   |
|   |       |       |   |
6   |   +-------+-------+   |
|           |           |
7   +-----------+-----------+

Play is divided into three stages, but the object throughout the game is to get three pieces in a line - called a mill. On forming a mill, one of the opponent's pieces is removed from the board and the game is won by the player who reduces an opponent's remaining pieces to two.

The opening stage begins with an empty board. Each player has nine pieces which are placed one at a time in turn on any vacant point on the board until both have played all nine. If a mill - a line of three - is made, the player making it removes any one of the opponent's pieces that is not itself part of a mill. Throughout the game, pieces forming a mill are therefore safe from capture.

Once a piece is removed from the board it takes no further part in the game. It is important to note that mills can only be made along the horizontal and vertical lines on the board, never across the diagonals where no lines are marked.

The middle stage starts when all the pieces have been used. Play continues alternately with the opponents moving one piece to any adjacent point. A couple of tactics are often used in this stage.

Firstly, once a mill is formed it may be opened by moving one piece from the line and closed by returning it to its original position in the next move. Alternatively, in a running mill opening one mill will close another one so that an opponent's piece is removed on every turn.

A player who is blocked, i.e. is unable to move any piece, loses the game, this is the way that many games are won.

The end stage allows a player with only three pieces to jump, i.e. to move one piece to any empty point on the board regardless of position. The other player must continue to move normally unless both are reduced to three pieces. The game ends when one player is reduced to two pieces and so can no longer form a mill.

### Move Notation

When placing a piece on the board at the beginning of the game, simply give the coordinates where the piece should be placed. e.g. D2

When moving a piece, give the source and destination coorindates. e.g. D2-F2

When you form and mill and capture a piece, give the coordinate of the piece you want to capture at the end of the move. e.g. D3,G1 (drop and capture) or A7-D7,B2 (move and capture)

## Nine Mens' Morris Links:

Rules courtesy of Cliff Hamer
http://www.tromboni.demon.co.uk/merrills/merrills.html