White
Black

Rules

The game begins on an empty board. Each player has a set of chess pieces of their color. The king is not in the game. On his turn a player can place a new piece and move it, or move an existing piece. When a piece moves, it leaves a trail on its path. The trails affect what moves are allowed. A trail must be at least two squares long, including the square with the piece. A player can capture a piece by cutting its trail short.

Drag the pieces from the racks onto the board and move them. Watching the dummy AI players for a minute is a good way get some intuition about the game before reading the rules.

A player wins when the opponent fails to make a move. For example, white wins if all black pieces on the board have been captured and the trails block placing and moving a new piece.

Placing new piece

Place a piece on any square that does not have a trail. Then make a move with it. The first move cannot cut trails or capture pieces.

Moving a piece

The pieces move as in the regular chess. Note that the board does not have orientation or the initial setup, so the pieces can be placed anywhere and move in any direction.

Knight's L-shaped move leaves an ambiguous trail - it can be either two squares then one, or one square then two. So after moving a knight a player may need to choose its trail.

The color of the pawn does not decide its direction. A pawn can even move sideways. After placing a pawn, move it toward the outside of its quadrant of the board. There are two choices of direction. The future moves of the pawn follow the same course. After a pawn reaches the far edge, it gets promoted to queen.

Moving over the trails

Only one trail can be on a square. When a piece moves through a square that already has a trail, the rules tell if it erases that part of the trail with its own, or if it must stop before crossing it.

A rule of thumb is that a piece can move over at most one trail. Crossing its own trail doesn't have any more conditions, a piece can move backwards or cut its trail at several points. Crossing a trail of another piece can only be done with a cut, intersecting it. More precisely, one trail cuts another when they have one square in common.

The cut trail gets split into two shorter trails. If they are too short, the piece is captured. If there are several valid trails, the player who did the cut chooses which trail to leave on the board. Now the piece whose trail was cut is at the end of the valid trail that remained.

About

This variant of chess was inspired by the game of go and the graph theory. The source code is available under GPL3.

Created by Boris Lykah. The name Trail Chess and the rules are public domain.

Creative Commons Licence
This work is licensed under a Creative Commons Attribution 4.0 International License.