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Help For Big Outer Chess
Introduction
Welcome to the network B.O. Chess server. The rules of B.O. Chess are below. The move notation is described on the help page for chess. Other commands are the same for all pbmserv games.
Copyright (c) 1999 Peter Blanchard All rights reserved
Rules of B.O. Chess
Intro and motivation
B.O. Chess is designed with two goals in mind. First, as with many large chess variants, B.O. Chess hopes to provide a spacious game. The second goal for B.O. Chess is to de-emphasize the center of the board by providing "outer" pieces which actually lose power when they move close to the center.
The board is 12 by 12 with an additional squares on each corner extending the main diagonals. The board is divided into 3 zones: The central zone consists of the 16 squares in the center of the board. The mid-zone surrounds the center and consists of the 48 squares which are no more than 2 squares away from a central square (diagonally or orthogonally). The outer zone consists of the remaining 84 squares around the edge of the board which are more then 2 squares away from the center. As will be explained fully below, the three outer pieces, the (outer) Knight, the Matriarch (Outer Queen), and the (outer) Jumper lose range as they move closer to the center. The Matriarch, for example, has the full power of a queen from the outer zone, but can't attack the king's square from the central zone! On the other hand, while she can attack the king's square from the mid-zone, she can't attack outer squares on the opposite side of the board. The initial position is shown here.
Z4 Z3
+---+ +---+
|*N*| a b c d e f g h i j k l |*N*|
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
12 |*J*|*R*|*M*|*G*|*B*|*Q*|*K*|*B*|*G*|*M*|*R*|*J*|12
+---+---+---+---+---+---+---+---+---+---+---+---+
11 |*P*|*P*|*P*|*P*|*P*|*P*|*P*|*P*|*P*|*P*|*P*|*P*|11
+---+---#---#---#---#---#---#---#---#---#---+---+
10 | |:::| |:::| |:::| |:::| |:::| |:::|10
+---+---#---+---+---+---+---+---+---+---#---+---+
9 |:::| |:::| |:::| |:::| |:::| |:::| | 9
+---+---#---+---#---#---#---#---#---+---#---+---+
8 | |:::| |:::| |:::| |:::| |:::| |:::| 8
+---+---#---+---#---+---+---+---#---+---#---+---+
7 |:::| |:::| |:::| |:::| |:::| |:::| | 7
+---+---#---+---#---+---+---+---#---+---#---+---+
6 | |:::| |:::| |:::| |:::| |:::| |:::| 6
+---+---#---+---#---+---+---+---#---+---#---+---+
5 |:::| |:::| |:::| |:::| |:::| |:::| | 5
+---+---#---+---#---#---#---#---#---+---#---+---+
4 | |:::| |:::| |:::| |:::| |:::| |:::| 4
+---+---#---+---+---+---+---+---+---+---#---+---+
3 |:::| |:::| |:::| |:::| |:::| |:::| | 3
+---+---#---#---#---#---#---#---#---#---#---+---+
2 | P |:P:| P |:P:| P |:P:| P |:P:| P |:P:| P |:P:| 2
+---+---+---+---+---+---+---+---+---+---+---+---+
1 |:J:| R |:M:| G |:B:| Q |:K:| B |:G:| M |:R:| J | 1
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|:N:| a b c d e f g h i j k l | N |
+---+ +---+
Z1 Z2
Basic Rules
As a main stream chess variant, B.O. Chess gets most of its rules from standard chess. All rules concerning draws, perpetual check, etc. apply. The game ends in the same way standard chess does: by check-mating the opposing king.
Piece Movement
Pawns may move up to 4 squares on their first move. After the first move a pawn may always move forward one or two squares except when moving to the last rank. A pawn may only move to the last rank by moving forward one square. A pawn reaching the last rank promotes to any piece except king or pawn. Thus it takes at least five moves for a pawn to promote. Except for en passent, pawns capture exactly as they do in standard chess. En Passent capture is allowed immediately following a turn in which a pawn has moved over the square attacked by an opposing pawn on an adjacent file. The capturing pawn moves in the usual way to the square it attacks. Note that En Passent capture is not only a possibility after a pawn's first move, but also after any pawn move of 2 squares.
The standard chess pieces: Rook (R,*R*), Bishop (B,*B*), Queen (Q,*Q*), and King (K,*K*) move and capture exactly as in standard chess. The ranges of the Rook, Bishop, and Queen extend to the entire board.
Castling is permitted under exactly the same rules as ordinary chess, except that the King moves 3 squares instead of 2. The squares between the King and the rook to be moved must all be empty and not under attack, and the King the rook may not have moved.
The Guard (G,*G*) takes the place of the ordinary knight in B.O. Chess. The guard moves and captures at any adjacent diagonal square, and also leaps and captures in a 3x1 "L"-shape: 3 squares forward, backward or sideways followed by one square in a perpendicular direction.
The Matriarch (M, *M*) (or Outer Queen) moves as a standard queen from the outer zone. A Matriarch on a square in the mid-zone moves as a standard queen, but no more than 6 squares in any direction. A Matriarch on a square in the central zone moves as a standard queen, but no more than than 3 squares in any direction.
The Jumper (J, *J*) is an outer piece which can always move and capture like a king, one square in any direction. In addition, a jumper in the outer zone may leap and capture exactly 3 squares forward, backward, sideways, or diagonally. In the same way, a jumper in the mid-zone may move one square in any direction, or leap and capture exactly 2 squares forward, backward, sideways, or diagonally. Jumpers in the central zone may move and capture only one square in any direction.
From the central zone the Outer Knight (N, *N*) leaps and captures exactly as an ordinary knight. From the mid-zone an Outer Knight leaps and captures "3x1" or "2x2": i.e. 3 squares forward or backward and 1 square sideways, 3 squares sideways and 1 squares forward or backward, or 2 squares forward or backward and 2 squares sideways. From the outer zone the Outer Knight leaps and captures "4x1" or "3x2".
Here is a diagrammatic explanation of the piece movements:
Outer Zone Middle Zone Inner Zone
================= ============= ============
*
*
m
Pawn c m c SAME SAME
P
|
Rook -- R -- SAME SAME
|
\ /
Bishop B SAME SAME
/ \
\ | /
Queen -- Q -- SAME SAME
/ | \
x x x
King x K x SAME SAME
x x x
x . x
.
x x . x x
Guard . . . G . . . SAME SAME
x x . x x
.
x . x
6 6 6 3 3 3
\ | / \ | / \ | /
Matriarch -- M -- 6 - M - 6 3 - M - 3
/ | \ / | \ / | \
6 6 6 3 3 3
x x x
. . . x x x
x x x x x x x x x
Jumper x . x J x . x x x J x x x J x
x x x x x x x x x
. . . x x x
x x x
x . x
x . . . x x . x
x . . . . . x x . . . x x . x
x . . . . . . . x x . . . . . x x . x
kNight . . . . N . . . . . . . N . . . . . N . .
x . . . . . . . x x . . . . . x x . x
x . . . . . x x . . . x x . x
x . . . x x . x
x . x
