Ubuntu Manpage: morris - Nine Men's Morris game for the Gnome desktop

NAME

       morris -  Nine Men's Morris game for the Gnome desktop

SYNOPSIS

       morris

DESCRIPTION

       Morris  is  an  implementation of the board game "Nine Men's Morris". Other names for this
       game are: Mills, Merrills, Morris, or Mühle in German. Nine Men's Morris,  being  probably
       2000-3000  years  old, appears to be one of the oldest board games, much older than chess.
       From the 12th to the 18th century, Nine Men's Morris was one of  the  most  popular  board
       games  in  Europe.  However,  it  is  still  actively  played  today and exists in several
       variants, e.g., Morabaraba, which is particularly popular in South Africa.

       This implementation of Nine Men's Morris supports not only the  standard  game,  but  also
       several  rule-variants  and different board layouts. You can play against the computer, or
       simply use the program to present the board, but play against another human opponent.  The
       computer opponent learns from previous games and tries not to make the same mistake twice.
       This ensures enough variation in game-play, should you  once  have  managed  to  beat  the
       program.

FEATURES

       Among others, the game plays the following variants:

           - Lasker variant (moves are also allowed in the set-phase)

           - The Möbius board (invented by Ingo Althöfer)

           - The Windmill board

           - The Windmill board

           - Pentagon and Hexagon boards

           - Morabaraba

           - Six and Seven Men's Morris

           - Tapatan, Achi, Nine Holes

       Furthermore, the game supports:

           - Advanced AI controls to tweak AI playing style

           - Giving hints for good moves

           - Showing the principal variation

           - Move takeback (undo and redo)

           - Internationalization (English, German, Chinese)

           - Many board and rule variations

           - Free customization of rules

           - Configurable display

STANDARD RULES

Each player has nine pieces (hence the name, Nine Men's Morris) which are placed and moved
on the line crossings of the board. Whenever three pieces of the same color are placed in
a straight row, a mill is closed and one opponent piece may be removed. The goal of the
game is to reduce the opponent to only two pieces (such that he cannot form a mill
anymore), or to surround the opponent pieces in such a way that there are no valid moves
for the opponent.

The game proceeds in three distinct phases (opening, midgame, and endgame). Unlike chess,
these phases are distinguished by special rules for each phase.

Opening - Setting pieces
The white player begins. Each player places one piece on an unoccupied position on
the board in turns. If a mill is closed by setting a piece, the player may take one
of the opponent's pieces. Once all pieces are set, the midgame starts.

Midgame - Moving pieces
Each player moves one piece along the lines to a free, neighboring position. Again,
if the move results in closing a mill, one of the opponent's pieces may be removed.
Note that a player must move a piece in each turn. If there is no legal move, the
player has lost.

Endgame - Flying
If a player has only three pieces left, he my jump (or fly) with one piece to any
unoccupied position instead of moving only along the board lines.

RULE DETAILS AND GAME VARIATIONS

Some of these rules are often interpreted differently, such that a variety of rule
variants exist. This game tries to support most of them. In particular, the following rule
variations are supported:

Taking from opponent mills
When a mill is closed, one opponent stone may be taken. However, usually, it is not
allowed to take a piece from an opponent's mill, if he still has pieces that are
not part of a mill. If you want, you can also allow players to take pieces from an
opponent's mill. Note that you can always take pieces from an opponent's mill, if
all of his pieces are within mills.

Multiple mills
In the setting phase, it may happen that two mills are closed simultaneously. In
the multiple-mills variations, the player may take two opponent pieces, in this
case.

Flying Some people prefer to omit the flying rule, such that only standard moves may be
conducted, even when a player is down to only three pieces.

Lasker variant (proposed by the chess grandmaster Emanuel Lasker)
There is no difference between opening and midgame. I.e., a player may decide to
move a piece instead of setting a new piece. Usually, this variant is played with
10 pieces instead of only 9.

Remis If the same board situation appeared for N times (with N usually 3), the game is
declared remis.

AI ALGORITHM

        The  AI  algorithm  is  a  standard  alpha-beta  search in a NegaMax implementation using
       iterative deepening. It employs a transposition table to quickly find previously  computed
       positions.

       A  special  feature  is  the  automatic learning capability: whenever the computer wins or
       loses a game, it will prefer to obtain or avoid similar situations  in  the  future.  This
       results  in  a  better  long-term  motivation,  since  the computer will not make the same
       mistake twice and the gameplay will be more randomized.

       The evaluation function is still quite basic and consists of four parts:

       Material
              The number of pieces each player has left

       Freedom
              The number of possible moves a player can conduct

       Mills  The number of closed mills

       Experience
              The learning-bias from previous games.