Stones and Relays

Stones & Relays

Stones & Relays is a straightforward chess variant. The pieces are exactly the same in number and movement as in FIDE chess, but the topology of the board is slightly more complex. The game is played on an 8x9 board, which has an additional row down the middle. It can easily be played on an ordinary chessboard by backing either the white or the black pieces off the rear edge. (Visualizing the extension of the square grid is quite easy.)

The board is altered more significantly by the addition of six neutral pieces: four stones and two relays. The opening setup is shown in Figure 1.

Figure 1. The opening setup in Stones & Relays. The relays are indicated in the ASCII diagram with the letter 'X.' White pieces are shown as capital letters; black pieces are lower-case letters bracketed by asterisks. Other opening setups are possible for the stones and relays; the main criteria are that the setup should be bilaterally symmetrical around the center row, and that the stones and relays should not all be clustered at the edges of the board. Left/right symmetry is not necessary.

  +---+---+---+---+---+---+---+---+
9 |*r*|*n*|*b*|*q*|*k*|*b*|*n*|*r*|
  +---+---+---+---+---+---+---+---+
8 |*p*|*p*|*p*|*p*|*p*|*p*|*p*|*p*|
  +---+---+---+---+---+---+---+---+
7 |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
6 |   | S |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
5 |   | S |   | X | X |   | S |   |
  +---+---+---+---+---+---+---+---+
4 |   | S |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
3 |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
2 | P | P | P | P | P | P | P | P |
  +---+---+---+---+---+---+---+---+
1 | R | N | B | Q | K | B | N | R |
  +---+---+---+---+---+---+---+---+
    a   b   c   d   e   f   g   h

The lengthening of the board has a significant effect on the development of knights and bishops. Both players' king's bishops can reach b5, for instance; they're no longer on opposing colors. And neither of these bishops can be used to pin the opponent's queen's knight after it moves to c3/c7.

The Stones and Relays

The stones and relays move one square per turn in any orthogonal (forward-and-back or side-to-side) direction. They are neutral pieces, and can be moved by either player. They can never be captured or removed from the board, and they have no power to capture other pieces or give check. They cannot move onto a square occupied by any other piece.

In each turn, the player must first move one of his or her own pieces, and afterward may move (optionally) a single stone or relay. A stone/relay move is not required in any turn.

Ko Rule. In order to prevent repeated positions, when your opponent moves a stone or relay from square A to square B, you can't immediately move it back to square A. You can, however, move it back to its previous position after another turn has elapsed.

The stones are blocks to the movement of other pieces. With respect to the movement of other pieces, a stone functions exactly like a friendly piece. During the opening, pushing stones across in front of your opponent's king and queen to impede development is a good idea; of course, your opponent will be trying to do the same to you.

A relay, in contrast, expands the movement power of pieces. Other pieces may not share a square with a relay, but they can cross its position. To look at it another way, when a piece's move ends on a relay, the piece "bounces." When a piece's normal move crosses (or, in the case of the knight, pawn, or king, would otherwise end on) the square occupied by a relay, the piece may continue its move, in any legal direction, as if the relay were the square on which it started the move.

The continuation of the move after crossing the relay need not be in the same direction as the beginning of the move: queens, bishops, and rooks can all change direction when crossing a relay. They retain their original type of movement, however. A bishop can continue only on a diagonal and a rook only on a row or column. The queen can switch from a diagonal to an orthogonal or vice-versa if desired when crossing a relay. A knight whose move would end on a relay can make a second move in any of its normal directions, starting on the relay square, as shown in Figure 2.

By reversing direction and returning to the square where it started, any piece (except a pawn) can use a relay to make a "null move." In effect, this allows the player to pass his or her turn.

Figure 2. With the help of the relay on e4, the knight on d2 can end its move on any of the squares marked 'o' (its normal moves) or '*' (by means of the relay).

 _ _ _ _ _ _ _ _
|_|_|_|_|_|_|_|_|9
|_|_|_|_|_|_|_|_|8
|_|_|_|_|_|_|_|_|7
|_|_|_|*|_|*|_|_|6
|_|_|*|_|_|_|*|_|5
|_|_|o|_|X|_|_|_|4
|_|o|*|_|_|o|*|_|3
|_|_|_|N|_|*|_|_|2
|_|o|_|_|_|o|_|_|1
 a b c d e f g h

A pawn can move onto a relay via either a capturing or non-capturing move. If it moves onto the relay by a capturing (diagonal) move, it must capture an enemy piece positioned on one of the two diagonal squares beyond the relay. If it moves onto the relay using a forward (non-capturing) move, it may either proceed forward beyond the relay, or capture an enemy piece positioned diagonally beyond the relay. If a pawn's two-square advance would pass through or end on a relay square, it may advance one or two squares past the relay, just as if the relay were where the two-square move started. A pawn can be captured en passant during the second leg of a double two-square advance. A pawn may also use a relay to make an en passant capture. However, a pawn may not capture another pawn en passant if the en passant square is the relay square itself.

Figure 3. The white pawn on c2 can use the relay to make an initial two-square advance to c6 (marked '.'). In this situation, it can be captured en passant by the black pawn on d6, or by a black pawn on d4, but not by a black pawn on d5 (see Figure 5).

 _ _ _ _ _ _ _ _
|_|_|_|_|_|_|_|_|9
|_|_|_|_|_|_|_|_|8
|_|_|_|_|_|_|_|_|7
|_|_|.|p|_|_|_|_|6
|_|_|_|_|_|_|_|_|5
|_|_|X|_|_|_|_|_|4
|_|_|_|_|_|_|_|_|3
|_|_|P|_|_|_|_|_|2
|_|_|_|_|_|_|_|_|1
 a b c d e f g h

Figure 4. The black pawn on e5 can use the relay on d4 to make an en passant capture of the white c2 pawn if the latter advances to c4.

 _ _ _ _ _ _ _ _
|_|_|_|_|_|_|_|_|9
|_|_|_|_|_|_|_|_|8
|_|_|_|_|_|_|_|_|7
|_|_|_|_|_|_|_|_|6
|_|_|_|_|p|_|_|_|5
|_|_|_|X|_|_|_|_|4
|_|_|_|_|_|_|_|_|3
|_|_|P|_|_|_|_|_|2
|_|_|_|_|_|_|_|_|1
 a b c d e f g h

Figure 5. The white pawn below can advance through the relay to the square marked '*'. However, the black pawn can't capture the white pawn en passant after this move, because its capture move couldn't end on the relay.

 _ _ _ _ _ _ _ _
|_|_|_|_|_|_|_|_|9
|_|_|_|_|_|_|_|_|8
|_|_|_|_|_|_|_|_|7
|_|_|*|p|_|_|_|_|6
|_|_|X|_|_|_|_|_|5
|_|_|P|_|_|_|_|_|4
|_|_|_|_|_|_|_|_|3
|_|_|_|_|_|_|_|_|2
|_|_|_|_|_|_|_|_|1
 a b c d e f g h

Stones can be moved through relays. Also, one relay can be moved through the other. If the two relays are properly situated, any piece can make a "double relay" move, as shown in Figure 6, below.

Because a player's move consists of a piece move followed by a stone or relay move, it is legal for the king to be in check after the piece move, provided that the stone or relay move removes the check. A stone can be used to block the check, for instance. The king can also move out of check via a relay.

Figure 6. A double relay move. The black queen on a7 can capture the white rook on c1 via the vector shown in the ASCII diagram with dots. As in an ordinary move, a friendly or enemy piece on any of the dotted squares would stop the queen's move.

  +---+---+---+---+---+---+---+---+
9 |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
8 |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
7 |*q*| . | . | . | . | X |   |   |
  +---+---+---+---+---+---+---+---+
6 |   |   |   |   | . |   |   |   |
  +---+---+---+---+---+---+---+---+
5 |   |   |   | . |   |   |   |   |
  +---+---+---+---+---+---+---+---+
4 |   |   | X |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
3 |   |   | . |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
2 |   |   | . |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
1 |   |   | R |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
    a   b   c   d   e   f   g   h

Figure 7. With the aid of stones (S) and relays (X), a bare knight can theoretically checkmate the opponent's king in many different ways, one of which is shown below. I'll leave it to those who are more experienced than I in endgame tactics to figure out whether black can be forced into this position, given that black can also move the stones and relays. Because a piece must be moved in a given turn before a stone or relay is moved, it's not possible for black to move the stone on b9 in order to make a square for the king to escape to. Square b8 is covered by the knight using a double relay move, and square a8 by a single relay from c9.

 _ _ _ _ _ _ _ _
|k|S|X|_|_|_|_|_|9
|_|_|_|_|_|_|_|_|8
|_|N|_|X|_|_|_|_|7
|_|_|_|_|_|_|_|_|6
|_|_|_|_|_|_|_|_|5
|_|_|_|_|_|_|_|_|4
|_|_|_|_|_|_|_|_|3
|_|_|_|_|_|_|_|_|2
|_|_|_|_|_|_|_|_|1
 a b c d e f g h

The Tunnel

If you're hankering for an added wrinkle, you can try playing Stones & Relays with a pair of neutral pieces called gates (G). The two gates are the ends of a tunnel or passageway between the two squares on which they sit. The ko rule also applies to gates. A suggested opening setup is shown below.

 _ _ _ _ _ _ _ _
|r|n|b|q|k|b|n|r|9
|p|p|p|p|p|p|p|p|8
|_|_|_|_|_|_|_|_|7
|_|S|_|_|_|_|G|_|6
|_|S|_|X|X|_|S|_|5
|_|S|_|_|_|_|G|_|4
|_|_|_|_|_|_|_|_|3
|P|P|P|P|P|P|P|P|2
|R|N|B|Q|K|B|N|R|1
 a b c d e f g h

As with the stones and relays, pieces can't occupy the same square as a gate. Because of this, only pieces that make multi-square moves can use the tunnel. In a tunnel move, the queen, bishop, or rook moves onto a gate square using its normal move and emerges from the other gate square, still travelling in the same direction. (Unlike a relay, the tunnel doesn't allow a piece to change direction.) Pawns can use a properly positioned gate in the middle of a two-square advance, but not otherwise. Knights and kings can't use the tunnel.

A piece can use the tunnel and also one or both relays in a single move. The stones and relays can't move through the tunnel, because they can only make single-square moves, but the gates can use the relays.

It's legal to check the enemy king by means of a move through the tunnel, but such a threat will have limited value, as the opponent can almost always eliminate the threat by moving one gate or the other.