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Growing and Shrinking:
Playing with the Size of Chess Pieces

`Curiouser and curiouser!' cried Alice (she was so much surprised, that for the moment she quite forgot how to speak good English); `now I'm opening out like the largest telescope that ever was! Good-bye, feet!' (for when she looked down at her feet, they seemed to be almost out of sight, they were getting so far off).  
 
Alice's Adventures in Wonderland
by Lewis Carroll

With all the discussion of halflings and turning pieces, I've been inspired to extend the discussion to the concept of pieces of different sizes. I know of two existing variants that use pieces that take up more than one square:

  1. Ganymede Chess
  2. Giant Chess

Perhaps there are others, but these are the only ones I can think of offhand. I will be discussing the large pieces from these games further down in this article.

Singleton Pieces

These are the pieces we're all familiar with -- they take up exactly one square. Hence they are said to have a size of one.

Twofold Pieces

A twofold piece is a piece that is double its normal size (ie, it takes up two adjacent squares instead of just one). The twofold piece moves by having each part of itself make the same move, so that for a twofold knight, each part of the piece would make the same knight move. It is possible for a twofold piece to capture two pieces in one move. You can think of a twofold piece as two normal pieces that always must move together with the same move. If they both can't make a certain move, then the piece as a whole can't make the move.

A twofold piece is captured if either of its components is captured.

We would consider this type of piece to have a size of two.

The Twofold Knight

The following diagram shows the squares a twofold Knight could move to. The squares are numbered 1-8, and squares with the same number represent the destination squares for a single move of the twofold knight. 
+---+---+---+---+---+---+
|   | 6 | 6 | 5 | 5 |   |
+---+---+---+---+---+---+
| 7 | 7 |   |   | 4 | 4 |
+---+---+---+---+---+---+
|   |   | NN|NN |   |   |
+---+---+---+---+---+---+
| 8 | 8 |   |   | 3 | 3 |
+---+---+---+---+---+---+
|   | 1 | 1 | 2 | 2 |   |
+---+---+---+---+---+---+

Here is an example of how a twofold Bishop might move: 

+---+---+---+---+---+---+
|   |   |   |   | x | x |
+---+---+---+---+---+---+
|   |   |   | x | x |   |
+---+---+---+---+---+---+
|   |   | x | x |   |   |
+---+---+---+---+---+---+
|   | BB|BB |   |   |   |
+---+---+---+---+---+---+

Examples of twofold pieces:

In Ganymede Chess, the Wall can be thought of as a twofold rook that also has the option of rotating.

Twofold Chess

+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| rr|rr | nn|nn | bb|bb | qq|qq | kk|kk | bb|bb | nn|nn | rr|rr | 8
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| pp|pp | pp|pp | pp|pp | pp|pp | pp|pp | pp|pp | pp|pp | pp|pp | 7
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   | 6
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   | 5
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   | 4
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   | 3
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| PP|PP | PP|PP | PP|PP | PP|PP | PP|PP | PP|PP | PP|PP | PP|PP | 2
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| RR|RR | NN|NN | BB|BB | QQ|QQ | KK|KK | BB|BB | NN|NN | RR|RR | 1
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
  a   b   c   d   e   f   g   h   i   j   k   l   m   n   o   p

Twofold chess is played on a 8 row by 16 column board. All pieces are twofold pieces. Pawns promote to either a twofold Queen, Rook, Bishop or Knight. There is no castling.

I suspect this game would be fairly awkward, with friendly pieces getting in each other's way too often.

Fourfold Pieces

These pieces are very similar to twofold pieces, except they occupy a 2x2 matrix of squares.

In Giant Chess, the Giant (Dev) takes up four squares (2x2), and moves in 2x2 square increments. For the purposes of this discussion, this piece could be thought of as a fourfold Dabbabah (see Dabbabah). Note however that this piece is more difficult to capture than an ordinary fourfold piece, as all of its squares must be threatened.

Double- and Quadruple- Pieces

Another possibility for double-sized (or quadruple-sized) pieces is to consider that they have the same move as their singleton cousins, except that we consider that move as using 'squares' of the same size as the piece that is moving. These pieces we will refer to with double- or quadruple- prefix.

Here is a diagram of the double-Knight's move: 

+---+---+---+---+---+---+---+---+---+---+
|   |   | 6 | 6 |   |   | 5 | 5 |   |   |
+---+---+---+---+---+---+---+---+---+---+
| 7 | 7 |   |   |   |   |   |   | 4 | 4 |
+---+---+---+---+---+---+---+---+---+---+
|   |   |   |   | NN|NN |   |   |   |   |
+---+---+---+---+---+---+---+---+---+---+
| 8 | 8 |   |   |   |   |   |   | 3 | 3 |
+---+---+---+---+---+---+---+---+---+---+
|   |   | 1 | 1 |   |   | 2 | 2 |   |   |
+---+---+---+---+---+---+---+---+---+---+

Here is an example of how a double-Bishop might move: 

+---+---+---+---+---+---+---+
|   |   |   |   |   | x | x |
+---+---+---+---+---+---+---+
|   |   |   | x | x |   |   |
+---+---+---+---+---+---+---+
|   | BB|BB |   |   |   |   |
+---+---+---+---+---+---+---+

The Giant (Dev) in Giant Chess could be considered as a quadruple-Wazir (see Wazir). Note however that this piece is more difficult to capture than an ordinary quadruple piece, as all of its squares must be threatened.

We could then devise Double Chess (I know the name's been taken), which would be like normal chess, except populated with double pieces. However, this game would be functionaly equivalent to normal chess!

Bifold Pieces

A bifold piece is a piece that takes up only 1/2 of a square, and hence is said to have a size of 1/2. Two bifold pieces may occupy the same square, even if they belong to different players. If a bifold piece moves into a square containing an enemy piece (normal sized), then the enemy pieces is captured. Similarly, if a normal size piece moves into a square containing one or two enemy bifold pieces, then the enemy pieces are captured. A normal sized piece cannot move into a square containing a friendly bifold piece (and vice-versa).

If a bifold piece moves into a square containing two enemy bifold pieces, then the moving player decides which enemy bifold piece is captured.

The general rule is that the sum of the sizes of the pieces in one square cannot exceed one. So a square could contain 1 singleton (normal sized piece), two bifold pieces, three trifold pieces, etc.

Bifold Chess

Normal array, but Rooks, Knights, Bishops and Queen are bifold. Kings and pawns are still singleton. Pawns promote to bifold Rook, Knight, Bishop or Queen.

Variations

Capturing

For twofold or fourfold pieces, we might consider that the entire piece is not captured if one of its components is captured. The piece would live on as a singleton, or threefold piece.

From Giant Chess -- for a piece of size two or more to be captured, all of its squares must be threatened.

For bifold pieces, we might consider that a bifold piece moving into the same square as an enemy bifold piece would capture instead of co-occupying the square.

Combining and Splitting

We could allow bifold pieces to split apart and recombine. We could allow pieces of different types to combine into bifold pieces (ie. a Knight and a Bishop might form a bifold piece that could move as either a Knight or a Bishop).

Other Ideas

I'm sure others can think of many more variations on this theme, so I'll stop now.

Written by David Howe.
WWW page created: 18 April 2001.