Birds and Ninjas

The game in a nutshell:

1. Each side has two Flying Bombers, two Ninja Guards, two Rooks, two Bishops, two Knights, King, Queen, 10 Pawns and 4 Ninja Pawns.
2. The game is played on a 104 square board with 2 extra squares that protrude from the center of each side’s back rank. These squares are "in-play" throughout the game just like any other square on the board.
3. The standard pawns advance 1-3 empty spaces from their start position and 1-2 spaces from the third rank (rank 8 for black) towards the center.
   En-passant is extended for these conditions. If a pawn bypasses an enemy pawn by moving 2 or 3 spaces forward it can be captured en passant.
4. A special type of pawn, the ninja pawn is dropped into an empty space of the 2nd rank.
   Like the regular pawn, it captures diagonally up and can shoot forward multiple empty squares toward the center. Additionally, it can move one space east or west.
   Once it passes the center it moves forward 1 space at a time but it gains the additional power of capturing sideways (1 space east or west).
   The ninja pawn can be dropped and moved forward simultaneously in one move. Each side can drop a maximum of 4 ninja pawns.
   The ninja pawn does not follow en passant rules.
5. The Flying Bomber is a new type of piece that moves passively like a rook but captures by flying over the enemy and landing on the empty square just beyond.
   It can also jump an adjacent piece, and if possible capture by replacement on the square it lands, two squares away orthogonally. If it jumps over an enemy piece when performing this special maneuver, it takes both enemy pieces in one move.
6. The Ninja Guard can make one diagonal step in any direction and jump two spaces diagonally. It captures by replacement and captures any jumped over enemy piece. It can also capture 2 pieces simultaneously like the flying bomber does.
7. The castling rules have been modified. The King can transpose places with the rook by moving multiple spaces towards it. There are a total of 7 castling positions.
8. Checkmate / Stalemate are identical to standard chess.

Setup

Coordinates for white. (black mirrors white) Ninja Guards on a1, j1 Rooks on b1,i1 Knights on c1,h1 Bishops on d1, g1 Queen on e1 King on f1 Flying Bombers on e0,f0. 4 Ninja Pawns off board.

Pieces

The Bird’s (Flying Bomber’s) Moves

*The flying bomber's shape resembles a bat, hence the iconographic symbols used. However, the flying bomber is also referred to as the "Bird" - a common nickname given to fighter planes. The choice of name is left to the player.

The flying bomber's odd combination of long-range and short-range moves makes it a deadly weapon against an unsuspecting opponent. As a rule, the bird moves along horizontal and vertical lines and never diagonally.

Standard Move:
• The flying bomber eliminates an enemy piece by flying over it, and landing on THE empty square immediately after it on the same orthogonal line. It cannot fly over or capture a second piece or land on any square beyond the first empty square.
• The flying bomber can fly along any amount of empty squares (1-9) orthogonally, but not over any friendly pieces. This is identical to the movement of a rook.
For a successful bombing, there must be an empty square immediately after the first enemy piece on the same line.

the Helicopter Landing Move

This is a special maneuver that enables the bird to fly over the adjacent square, (jumping over, if occupied by friendly piece or eliminating if occupied by enemy piece) and land like a helicopter on a square exactly 2 squares away, capturing if possible on this square. Thus, it can capture two pieces in this manner.
Essentially, it combines its standard move with that of a two space orthogonal jumper. It jumps the adjacent square to land on the next square two squares over.
This peculiar short-range prowess in more detail:
• The Flying Bomber can fly over one friendly piece adjacent to it (left, right, up or down) and land on an empty square immediately after it. When it flies over an adjacent friendly piece, its range is limited to two squares.
• If an enemy piece is exactly 2 squares away orthogonally and no other piece is in-between, then the flying bomber can capture the usual way by flying over it and landing on the empty square after it. It can also capture by landing on the same square as the enemy like a Helicopter.
• If two enemy pieces lie on the same line, the first one adjacent to the flying bomber, and the next two squares away, then it can eliminate both pieces by landing on the square of the second enemy piece. (see diagram 1) It cannot fly over the second enemy piece.
• Similarly, if there was a friendly piece in immediate vicinity of the flying bomber, and an enemy piece right after it, then the bird can fly over the friendly piece and destroy the piece right after by landing on the same square. Here too it cannot fly over beyond the enemy piece as it cannot fly over two pieces.
• The Flying Bomber needs at least one square to fly over for a bombing. e.g. it can destroy any enemy piece in its vicinity (1 square to left, right, up or down) by flying over it and landing on the empty square after it, but if a friendly piece occupies a square immediately after the enemy piece, no capture can be made. (see diag 2)

It is easier to remember the flying bomber moves as a combination of the standard move with the move of the Dabbabah - a leaping move two squares in any orthogonal direction.



diag 1 (sideways rook rep. flying bomber)	Diag. 1: The flying bomber on f4 is posing multiple threats to black's pieces. It is threatening to destroy the black bishop on f7 by moving f4-f8. Using its special 2 square helicopter capability, it is threatening the black rook on d4 by moving f4-d4 (flying over its own piece and bombing/landing on d4). It cannot land on any squares beyond d4. This same short-range prowess gives it the ability to threaten f4-h4, flying over and bombing pawn on g4 and landing/bombing rook on h4. Note that the bomber cannot move to g4 by capturing the pawn, it must eliminate both the pawn and the rook. If there was no rook on h4 then the bomber can just capture the pawn by moving f4-h4. Note that the bird IS giving check to the king because it is exactly 2 squares away, and the bird can land on f2. However the bird is not threatening the knight on f1 since it is more than 2 squares away and there is no empty square beyond it. If the king moves, the knight will not be under attack either.
diag 2 (sideways rook rep. flying bomber)	Diag 2: Here the Flying Bomber is hampered by Black’s Pieces. It is not checking the king at d7 because there is no empty square behind it (and it is not exactly 2 squares away from it). The rook on d8 is pinned, because moving it would enable the king to be captured. However, the king can simply move away and the rook on d8 is not threatened because there is no empty square beyond it. The rook on e4 is adjacent to the flying bomber and threatening it. But the Flying Bomber cannot do anything because the white pawn occupies f4 and the bomber needs an empty square after its target. If f4 was an empty square, the bomber could capture the rook, and if there was another enemy piece on f4 instead of the white pawn, then the bomber could have captured both pieces. The Flying Bomber does attack the pawn on d2. It can play d4-d1 OR it can even play d4-d2 to eliminate the pawn. Because it is 2 squares away, the bomber can land on the same square as its target.
diag 3 (sideways rook rep. flying bomber)	Diag 3: Here the black Flying Bomber is threatening white’s pawns at d4 and a7. However, the white bishop is defending both pawns (colored squares). To make matters worse the bishop is also attacking the bird!




The Ninja Guard’s Moves

The Ninja Guard is a color bound piece that can move one or two steps diagonally. It can leap over a diagonally adjacent friendly piece to land exactly 2 squares away (a two-space diagonal leap). It can capture on any square it lands, and additionally it can can capture an enemy piece that is diagonally adjacent by jumping over it. It can capture two pieces (the first immediately adjacent to it, and the next right after) in its path on a diagonal by jumping over the first one and capturing the second piece on the square it lands.

The Ninja Guard on d4 can capture all the pieces in the diagram. It can capture the pawn on b6 by jumping over the knight at c5. It can capture the knight on c3 by moving to c3 or by jumping over the knight and landing on b2. It can capture the rook on e5 by moving to e5 or it can capture both the rook and the pawn by jumping over to f6.




The Ninja Pawn

The ninja pawn possesses slightly different modes of movement and capture depending on which half of the board it is on.

Movement:
The ninja pawn can always move 1 square up or 1 square sideways to an empty square regardless of where it is situated on the board.

When the pawn is situated in the lower half of the board (for White, rank 0-5 and for black 11-6), it can move forward multiple vacant squares to reach the middle of the board (rank 5 for White or rank 6 for Black). This move can be done at any time regardless of how many times the pawn has moved. Thus White can on each turn move from e2-e3, e3-d3 and d3-d5.


Once it passes the middle, the ninja pawn can only move 1 square forward at a time, or move 1 square horizontally.

Capture:
Like the standard pawn it can capture one square diagonally up, regardless of which half of the board it is on.
When the ninja pawn is on the top half of board (White rank 6 +, Black rank 5-) , it can also capture one square horizontally.

There is no en passant. It cannot capture another pawn or ninja pawn en passant nor can any other pawn capture it this way.

Promotion: The ninja pawn promotes on the last row (rank 10 for white, rank 1 for black), to any piece. Promotion to a piece is mandatory so it would cease to be a pawn in the last row.

Dropping:
The ninja pawn is not present at the start at the game and is dropped by the player into the drop zone, which are the 2nd rank squares. For example, the drop zone for white is a2-j2 and for black a9-j9.
The square must be vacant to drop the pawn. You can drop a pawn to check or to checkmate the opposing king A maximum of 4 ninja pawns can be dropped by each side during a game.
After dropping a pawn, the player can optionally push the ninja pawn forward 1 or multiple squares towards the center on the same move. A capture is not permitted during the drop, so the player can just drop a pawn, or drop a pawn and move it 1-3 vacant squares towards the center.

In diagram, the black ninja pawn can go from e9-e6 or any other square in between or d9 or f9. The white pawn at f7 cannot capture it en passant Lets say the white ninja pawn went from e3-f3 , it still has the option of shooting forward to the middle (f5) regardless of how many moves it made before. e.g. it can go e2-e3, then e3-f3 . It can now (see diagram) go f3-f5 if unobstructed. The white ninja pawn at h9 can capture the bishop at i9 in addition to being able to go to g9 or to promote by going to h10.

Rules

The rules in Birds and Ninjas are the same as in chess except for using the new pieces and for the following modifications :
1. Castling: The usual castling criteria apply: No pieces between the king and castling rook, cannot castle out of check, King cannot pass over or land on squares attacked by enemy, but rook can.
   There are 7 possible castling positions: The choice of castling positions will depend on whether it is immediately necessary for the king to be closer to the wing or for the rook to be more centralized. Note that the rook must always be next to the king after castling.
   1. 1 space transposition - King Side Castling
      White moves King one space from f1-g1 and rook from i1-f1
      Black moves King one space from f10-g10 and rook from i10-f10
   2. 1 space transposition - Queen Side Castling
      White moves King one space from f1-e1 and rook from b1-f1
      Black moves King one space from f10-e10 and rook from b10-f10
   3. 2 space transposition - King Side Castling
      White moves King two spaces from f1-h1 and rook from i1-g1
      Black moves King two spaces from f10-h10 and rook from i10-g10
   4. 2 space transposition - Queen Side Castling
      White moves King two spaces from f1-d1 and rook from b1-e1
      Black moves King two spaces from f10-d10 and rook from b10-e10
   5. 3 space transposition - King Side Castling White moves King three spaces from f1-i1 and rook from i1-h1
      Black moves King three spaces from f10-i10 and rook from i10-h10
   6. 3 space transposition - Queen Side Castling White moves King three spaces from f1-c1 and rook from b1-d1
      Black moves King three spaces from f10-c10 and rook from b10-d10
   7. 4 space transposition - Queen Side Castling White moves King four spaces from f1-b1 and rook from b1-c1
      Black moves King four spaces from f10-b10 and rook from b10-c10
   The ninja guard can remain at j1, j10, a10 or a1 when castling.
   
2. Pawn initial moves: A pawn situated on the lower half of the board can at any time move forward 1-3 vacant squares to reach the center of the board (rank 5 for white, rank 6 for black). Once the pawn reaches the center row, it can move forward only one square at a time.
   Some examples: The white pawn at f2 can start f2-f5 or it can move f2-f4 then f4-f5, or f2-f3 followed by f3-f5, or move f2-g3 to capture enemy piece at g3 followed by g3-g5 next time it moves.
3. En Passant: If a Pawn moves two or three squares initially and passes an opposing Pawn on the fourth or fifth rank, the Pawn may be captured en passant. E.g. White pawn on a2 black pawn on b4. If the white pawn moves from a2 to a4 or a5, the black pawn on b4 can capture it as if it had moved to a3. Similarly, if the black pawn is on b5 instead and the white pawn moves to a5 from a2 then the black pawn can capture the white pawn as if it moved to a4. Note in this case the white pawn can still avoid the black pawn by moving to a3 instead.
   If a pawn slides forward 2 squares on its second move, it can also be captured en passant by an opposing pawn on the fifth rank. E.g. white pawn on a3 and black pawn on b5. White plays a3-a5, black pawn on b5 can capture the pawn en passant by moving to a4.
   Capturing en passant is optional unless it is the only legal move available. The capture must be made on the next move.
4. Pawn promotion: Pawns can now promote to: queen, bishop, knight, rook, ninja guard or flying bomber on the 10th rank only.
5. Ninja pawns can be dropped (as described above) along with an optional forward move. En passant does not apply to them and they must promote as a normal pawn does.

Strategical Considerations

• The larger board increases the distance between the two armies, allowing each side to develop their pieces effectively for a more prolonged attack. White's opening advantage is nullified, and the variety of new undiscovered openings ensure that neither side resorts to cheap tactical tricks and/or a memorized set of opening moves.
• The two additional squares in the center of each side constitute the rear of the "palace". It makes a great hideout for the king, provides an alternative to castling, and can kindle a variety of interesting battle plans.
• The new pieces - the Birds (Flying Bombers), which capture by flying over their victims, prove to be formidable weapons and compliment the rooks perfectly. They also exhibit excellent defensive powers, and their unique short-range jumping abilities inject a more harmonious balance to the game.
• The ninja guard, despite its fierce short-range and double capture capabilities controls only 8 squares making it the perfect complementary piece to the knight.
  
• The Ninja Pawns are very effective if advanced into enemy territory since they control the adjacent spaces to their left and right.
• Relative Value: The value of the flying bomber relative to the rook is hard to determine, but as a general rule, the rook is a bit more powerful than the flying bomber, whose action can be blocked, and which cannot attack pieces more than 2 squares away on the edge of the board.
  It may be difficult at times to defend against a flying bomber since it lands on the empty square beyond the capturing piece.
  An approximate set of values:
  Ninja Guard=Knight=3 pawns (ninja guard ~3.25-3.5)
  Bishop=4 pawns
  Flying Bomber=5pawns. (~5.25-6.25)
  Rook=6pawns
  Queen=11 pawns.

Notes

For the record, some of the older rules and experimental sub-variations are listed below:

The game was released originally with no ninja pawns and a different start position. The ninja guards were next to the bishops and the rooks on the a and j files. There was also a second board position very similar to current but the flying bombers and the ninja guards’ positions were switched. This was used mainly for the birds and leaping ninja guards variation in which the ninja guards could also leap like camels. This variation was tried out and it seemed that the board position was superior but the long leaping pieces were not necessary.
The presets for the old versions are still available.

The flying bomber was capable of landing on ANY empty square after the enemy piece. Consequent play-testing proved that this was disastrous for pawn structures and it was changed soon after. The game Flying Bombers Chess still retains the old version.

The ninja pawn variation was introduced but the restriction was that the pawns could only be dropped in the rear center squares. Also the pawns could not move forward until the next move. This was changed to dropping in backrank/2 outer squares and finally to the current scenario from results of play-testing.

The sub-variant Birds Only was released as a new game Raptor Chess.

Capture the Scepter rules were introduced as a sub-variation. Basically, a side can win if its king can position itself on the enemy’s rear squares. This rule is interesting but not necessary for this game.

Insane Ninja Knight promotion also utilized the rear squares to promote the knights and ninja guards to the more powerful insane ninja knight.

I found it necessary to downplay the above sub-variants so as to emphasize the preferred rule-set and setup for this game. While I have created many other chess variants, I still regard this as my number one game. On retrospect, the subtlety of this system is truly astounding.


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By Charles Daniel.
Web page created: 2007-10-11. Web page last updated: 2008-07-12