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# Touring Chess

### By Ralph Betza

Touring Chess is a game of partial information, and cannot be played without a moderator.

The best known partial-info chess variant is Kriegspiel, in which the players do not see each others' pieces. In Touring Chess, you know where the pieces are, but you do not know the full topography of the board.

In Kriegspiel, the players have less information, and therefore Kriegspiel is a purer (more extreme) game of partial information than Touring Chess.

In Kriegspiel, several interactions between a player and the moderator may happen each move. This works well when the two players and the moderator are all in the same room (or when they are walking down the street playing blindfold).

In Touring Chess, many moves do not require the moderator's intervention, and no move ever requires more than one interaction between a player and the moderator. Therefore, Touring Chess is much more convenient than Kriegspiel when you play by email or even by snail mail.

## Basic Concepts

### The Knight's Tour

A Knight's tour is a series of 63 Knight moves that visit each square exactly once.

A reentrant, or "closed", Knight's tour is a Knight's tour where the last move is a Knight's move away from the starting position.

Many different Knight's Tours can be composed.

Complete information is given by the renowned mathematician, chess-varianteer, and chess problem composer Mario Velucchi.

### The Knight's Tour Chessboard

The Knight's Tour Chessboard has a magical connection from each square to the next step of a Knight's Tour. A Touring Move follows this path.

### Touring Moves

If you know the shape of the Knight's Tour, a touring move is simply an extra power for your piece, but if you do not know it, a touring move is a leap into the unknown.

For example, suppose that you begin the game by making a touring move with your Pawn at g2; you do not know whether the Pawn will go to h4, f4, e3, or e1. If the Pawn goes to e1, it captures your King and you have lost the game.

### Known Touring Moves

After the move 1. Ra1xc2, both players know that a touring move from a1 will go to c2; they also know that touring from b3 goes to a1.

When a touring move is made along a known path, there is no need to send the move through the moderator.

You can, if you wish, capture your own pieces with a "Known Touring Move".

### Historical Note

The Knight's Tour Chessboard was previously used in my game "Brownian Motion Chess", of the early 1970s, a game which was never seriously intended to be played: after each turn, every piece makes a touring move!

The touring moves are simultaneous, so there are no touring captures.

Brownian Motion Chess is a more extreme form of Pinwheel Chess.

Bill Rawlings suggested a possibly playable variant called "List Chess", in which pieces are rotated according to a numbered list of the squares which have been moved to. When a square is repeated on the list, all squares after its first mention are deleted. Sample game was 1. f4 d5 (the Pawns trade places by rotation) 2. Nc3 (Nf4 Black Pd5 White Pc3) Nf6 (BNf4 WNd5 BPc3 WPf6) 3. Nd5xf4 (the list is truncated so no rotation takes place) c3xd2 (d2 and f4 change places) with a deadly check -- the Black P at f4 is going to rotate back to d2. (Castling adds no squares to the list; no rule specified for Pawn promotion by rotation.)

## Touring Chess

The moderator prepares a Knight's Tour before the start of the game.

The players do not see the Knight's Tour.

Each turn, each player may make a normal move or a Touring Move.

In order to make a touring move, the player tells the moderator "touring from e4" (or whatever square it starts from), and the moderator sends to the opponent "e4-g5" (or whatever the actual move was).

Normal moves do not require intervention by the moderator, however when a player makes a Knight move it should be sent through the moderator. For example, after 1. e4 e5, if Black receives the move 2. Ng1-f3 from the opponent, it is known that it was a normal move; but if the move 2. Ng1-f3 comes from the moderator there is no way of knowing whether it was a touring move or a normal move.

Pawns that reach their own first or eighth ranks by touring have no normal moves; they may leave only by another touring move.

Kings may not make touring moves.

A touring move may capture your own piece. If you capture your own King, you lose.

### Touring Check

After the moves 1. e4 e6 2. Nh3 Ne7 3. e5 d5 4. Ng5 Nf5, White can play 5. Ng5xf7, forking Q and R, and therefore Black must capture the Knight with 5...Ke8xf7; and now of course the Pawn at e5 will make a touring move!

White gets one chance in eight to capture the enemy King, but the other seven cases are wins for Black because White has given up a Knight.

Therefore in this example, Black benefits by exposing his King on f7 to a Touring Check from the Pawn at e5.

## Other Ideas

Alice's Touring Chess should use two different Knight's Tours.

Doublemove Touring Chess requires you to make a normal move and then a touring move.

Guidebook Touring Chess allows a player to ask where a touring move would go, at the cost of skipping a move. The opponent, of course, doesn't find out the answer.

Written by Ralph Betza.
WWW page created: January 20th, 2003.
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