Interweave

By Peter Aronson

Introduction

          Interweave is a game where all pieces are colorbound, but can only capture pieces on squares of the opposite color. Needless to say, capture is not by replacement; instead short and long leap, custodian, rifle and approach captures are used instead. You must capture when you can, and a piece may make multiple captures in a turn. The must capture rule, combined with the number of methods of capture, results in a game that plays a bit like Checkers crossed with Ultima. The goal of Interweave is to capture either of your opponent's two Kings.

Board and Setup

          Each player starts with 8 Pawns, 2 Smashers, 2 Leapers, 2 Removers and 2 Kings.

  +---+---+---+---+---+---+---+---+
8 | s |:r:| l |:k:| k |:l:| r |:s:|
  +---+---+---+---+---+---+---+---+
7 |:p:| p |:p:| p |:p:| p |:p:| p |
  +---+---+---+---+---+---+---+---+
6 |   |:::|   |:::|   |:::|   |:::|
  +---+---+---+---+---+---+---+---+
5 |:::|   |:::|   |:::|   |:::|   |
  +---+---+---+---+---+---+---+---+
4 |   |:::|   |:::|   |:::|   |:::|
  +---+---+---+---+---+---+---+---+
3 |:::|   |:::|   |:::|   |:::|   |
  +---+---+---+---+---+---+---+---+
2 | P |:P:| P |:P:| P |:P:| P |:P:|
  +---+---+---+---+---+---+---+---+
1 |:S:| R |:L:| K |:K:| L |:R:| S |
  +---+---+---+---+---+---+---+---+
    a   b   c   d   e   f   g   h

Rules

          The rules of Interweave are identical to those of International Chess, except when noted below. The largest general rules change is that the object of the game is to capture the an opposing King, not to checkmate one. A stalemated player loses, and three-times repetition is a loss for the repeating player, not a draw.

          The second largest change is that captures are obligatory: if it is your turn and you have potential captures, you must choose and perform one of them. If, after you complete the selected capture, your piece that made the capture has more possible captures, you must perform one of those too. This continues until you have no more possible captures for the moved piece. Captured pieces are removed immediately, and are not barriers to further capture. A Pawn that promotes as the result of a capturing move is still obliged to capture if, with its new powers of capture, it now has any captures available. You are not required to choose a move that results in the greater number of captures, as you are in International Draughts.

The Pieces and their Movements

Piece	Description
King	The King moves without capturing one square diagonally. The King captures by a short orthogonal leap. The King may move without capturing to any of the squares marked with a green circle. The King may capture either of the black Pawns by leaping over them and landing in a square marked with a red circle. There is no castling.
Smasher	The Smasher may slide any distance diagonally without capturing. It may slide orthogonally as well, potentially capturing, but may only stop on squares of the same color as the square it started on. It may not leap over pieces in the way. If the next square in the direction it moved from the square it stopped on is occupied by an opposing piece, that opposing piece is captured. (This is capture by approach.) The green circles indicate where the white Smasher can move without capturing, and the Red circle indicates where it may move to to capture the Pawn just above it. Note that it can not capture the black Pawn to the lower right as the Pawn is on the same color as the Smasher, so it can not reach the square just before it to capture it.
Leaper	The Leaper may slide any distance diagonally without capturing. It may slide orthogonally as well, potentially capturing, but may only stop on squares of the same color as the square it started on. It may also make a double Knight's move (two over and four up, or four over and two up), possibly capturing, as long as there isn't a friendly piece at the midpoint of the move. Other than the midpoint, the double Knight's move may pass over pieces of either side. As might be expected from its name, the Leaper captures by making long leaps over opposing pieces on squares of the other color from which it starts. Capturing orthogonally, the Leaper moves up, down, left or right until it reaches the target piece, jumps over it, then lands some distance in the direction of movement beyond the piece captured on a square of the color it started on. A Leaper may also capture an opposing piece a Knight's move away, as long as the space a second Knight's move past the captured piece is empty for the Leaper to land in. Red circles indicate squares the could be landed in after leaping over and capturing an opposing piece, green circles indicate squares move to without capturing. The "x" indicates the square that has to be empty for the noncapturing double Knight's move to be made.
Remover	The Remover may slide any distance diagonally without capturing. It may capture any orthogonally adjacent opposing piece without moving. The above Remover could capture either black Pawn (and then it would be required to capture the other), or move without capturing to any square marked with a green circle.
Pawn	Interweave Pawns move sort of like a cross between a checker, a Berolina Pawn and an Ultima Pincher Pawn. A Pawn may move one square diagonally forward to an empty square, and optionally may move a second square in the same direction to another empty square when making its first move (and they may be captured en-passant by short leap when so doing). Pawns capture by a short leap forward, and by orthogonal custodian capture (also known as interception and sandwiching) where the Pawn moves to complete the sequence FEP (Friend, Enemy, Pawn, or Pawn, Enemy, Friend), capturing the enemy piece in the middle. Custodian capture may be combined with short leap capture. A Pawn can capture up to four opposing pieces at once. In the lower left we see a Pawn moving without capturing to the squares marked with green circles, including a potential double move as its first move. In the upper left, we see a Pawn moving to the square with a red circle to perform a double custodian capture. In the middle we see a Pawn performing a capture by short leap, and on the right a combined capture by short leap and by custodian capture. A Pawn that reaches the second-to-last rank of the board may promote to any previously captured non-Pawn piece of that side not yet returned to play. Upon reaching the last rank, the Pawn is required to promote; if there are no pieces available for promotion, then a Pawn may not enter the back rank. If the Pawn reaches a square on which it promotes by making a capturing move, after promoting, the promoted piece must continue to capture if it is able.

Notes and Comments

          I've been pondering the idea for a while of pieces that, while colorbound, can capture pieces on the other color. From there came the leap to Interweave: what if all pieces were colorbound, and could only capture on the other color? Thus, this game. It is named Interweave as each side is essentially playing two interwoven games at once.

          The first version of Interweave, which did not have forced or multiple captures was very drawish. Given that so many of the capturing methods were so weak, it seemed reasonable to make capture obligatory and multiple. Adding that seemed to give the game the dynamics it needed.

          I got capture by short leap from Anglo-American Checkers, capture by long leap from International Draughts, capture by approach from Fanorona, and custodian capture from a whole pile of ancient games (all of these forms of capture show up in other places, of course).

Equipment

          Interweave can be played with a normal Western Chess set by using the Pawns as Pawns, Bishops as Removers, Knights as Leapers, Rooks as Smashers, and the King and Queen both as Kings.

Computer Play

          I have written an implementation of Interweave for Zillions of Games. You can download it here:

• interweave.zip