The Game of Unlur
An
introduction to this challenging board game. Invented
by Jorge Gómez Arrausi, Unlur won the 2002 Unequal Forces Game Design
Competition
organised
by the Abstract Games magazine. It is one of the games that can be
played online on the
Gorrion Server. Please do try it.
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(
A game
in
progress. It is black to move. )
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The Game
The
game is a connection game played between
two people across a hexagonal board. Both players take turns to place a
piece on the board. The objective is to be the first to complete a
chain
of pieces that connects edges of the board. The player with the black
pieces
attempts to create a Y, a chain that connects three non-adjacent edges
of the board while the player with the white pieces attempts to create
a line, a chain that connects opposite edges of the board. Corners are
common to both of the adjoining sides.
(
Winning connections. )
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The Foreign Connection
Both players aim
to
create
a winning connection yet the following diagrams show positions in which
black cannot form a Y and in which white cannot form a line.
(
Foreign
connections. )
To avoid such
situations, the following rule was
introduced. A player
will lose if he creates a connection that the other player needs to
get.
For black this is a connecting line and for white this is a connecting
Y. So, black aims to create a Y but has to avoid forming a line, and
white
aims for a line and needs to avoid a Y. Corners are common to both of
the
adjoining sides. In the diagrams above black has lost because he has
created
a losing line ( left ) and white has lost because he has created a
losing
Y ( right ). The rule guarantees that one of the players will
eventually
win. The rule permits a player to make a move that simultaneously
creates
both a winning and a foreign connection. That player will have won.
( Winning even though the foreign connection has
been
created. )
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The Contract Battle
White has an
advantage
because it takes fewer moves to create a line than to create a Y.
To make the game equal Black needs a few compensation pieces.
This is
a feature that is unique to Unlur. The players start by playing out a
short contract battle to decide the colours. They
take turns to place a black piece on the
board
until one of the players feels that the black pieces are
sufficient
to counterbalance the white advantage and declares that he will play
the
remainder of game with the black pieces. The game then continues with
the
other player taking the white pieces and making the first white move.
There
is only one rule: a black piece cannot be placed on the edge of the
board during this contract phase
( because an edge placement can be a weakness for black. )
In the following
game
white has just made his first move. The chances for both players are
considered to be fairly equal.
( Equal
chances. )
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The Game Board
The game
can be played on a range of board
sizes. Size 8 ( 8 cells along each edge ) should be the minimum for a
good game. Size 10 for more serious play. Size 12 if you want a deep
and challenging battle.
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Winning Patterns
There are
three winning patterns that can occur. A winning pattern
makes it impossible for one of the players to form a winning connection
and a win will automatically fall into place for the other player.
The
Three Edges Pattern.
The following diagram illustrates a winning pattern for
black. White cannot win because he needs one of the edges that
are controlled by black.
The Two
Edges
Pattern.
The following diagram illustrates a winning pattern for white. White
controls two opposite edges and one of them is needed by black in order
to create a Y. White, however, can create a winning line.
The
Opposite Edges Pattern.
The following diagram illustrates another winning pattern
for white. Both black and white have control of opposite edges and
their chains of pieces touch. Black
cannot win because he will form a
losing line if he attempts to create a Y. White, however, can create a
winning line.
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More Information
Links. An article
about Unlur following its success in the Unequal
Forces Game
Design Competition used to be available at the web site of the Abstract
Games
Magazine at [ http://www.abstractgamesmagazine.com/unlur.html
]. An archive copy
is available at [ Archive
- Unlur ].
The
GoRilla
Game Editor. GoRilla is an SGF
reader that can be used to analyse and
review games of Unlur (
and also of Go / WeiQi / Baduk, Havannah,
Othello / Reversi, Hex and Kropki ). It is a compact,
non-commercial
program, and is available from my web page [ gorilla.html
]. I hope you will find it a useful product.
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The Gorrion Game Server
Unlur is one of the games played online on my game
server, Gorrion.
[ http://www.dashstofsk.net/gorrion.php
]. Please do join in the fun. I am 'dashstofsk' at the server and will
welcome all
challenges to a game.
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