The Ninja Pawn

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 1-5 and for black 10-6), it can move forward multiple vacant squares (1-3 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.

From the middle, (rank 5 for white, rank 6 for black), the ninja pawn just moves 1 square forward per turn.

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.
Note that like the standard pawn, only at rank 5 for white or rank 6 for black is the pawn compelled to go one space forward, and it can reach the promotion square from its start position in a minimum of 4 moves!

Dropping: 5 Ninja Pawns can be dropped (1 per turn) into an empty space on the 2nd rank by either side during the course of play. The Ninja Pawn can be optionally pushed forward (1-multiple spaces) towards the middle during the same turn.
It cannot make a capture on the same turn as the drop.

Sorcerer Snakes

Here each side starts off with 2 Sorcerer Snakes and ability to drop 5 Ninja Pawns.

Octopus and Snake with Stepping Knights

This deviates from the spec for Pick the Piece Big Chess by replacing the Knights with the Wazir (orthogonal stepping) and Ferz (diagonal stepping) Knights. Otherwise it is same as the main game: Octopus and Snake Chess.

Terror Freeze

Each side starts off with 2 Terror Freeze pieces and with chance to drop 5 ninja pawns during play.
The Terror Freeze moves passively like queen or knight and immobilizes all adjacent enemy pieces except pawns, ninja pawns and knights.
Immobilized pieces cannot move nor attack nor can they check a king.

Detonators

Each side starts off with 2 Detonators and with chance to drop 5 ninja pawns during play.
During a turn, the Detonator can be used to destroy all adjacent enemy pieces except Ninja Pawns.
It does not move when detonating. Otherwise, it moves like a queen or knight without capturing.

Dragons

Each side starts off with 2 Dragons and with chance to drop 5 ninja pawns during play.
Moves without capturing like a queen or knight.
Captures by sliding towards enemy piece and stopping short in forward directions N, NE, NW
Captures by withdrawing from an enemy piece in backwards and sidewary directions S, SE, SW, E and W. e.g. if it moves east any adjacent piece west of it is captured.
It CANNOT capture pawns or Ninja Pawns.

Carnage!

Here, each side starts off with a Dragon and an Terror Freeze.
A Detonator can be added during play via any empty square on back rank. Dropping the detonator takes a turn.
5 Ninja pawns can be dropped into the 2nd rank as well.

Super Power Arms Race

Each side starts off with a Ninja Warrior Bishop and a Ninja Guard Rook.
The Ninja Guard Rook - moves like a Rook and like a Ninja Guard: - a diagonal 1 step/2 space jumper that can capture jumped over enemy pieces in addition to the capturing by replacement.
The Ninja Warrior Bishop - moves like a Bishop and like a Ninja Warrior: - an orthogonal 1 step/2 space jumper that can capture jumped over enemy pieces in addition to the capturing by replacement.
Drop the Chancellor (Rook-Knight) and Archbishop (Bishop knight) on any empty square in the backrank to further power up in this arms race!
5 ninja pawns can be dropped via an empty square in the 2nd rank as well

Capablanca Game

Here each side uses the Archbishop and Chancellor
The Archbishop moves like a bishop or a knight.
The Chancellor moves like a rook or a knight

Capablanca Game - No Ninja Pawns

Same as above but without ability to drop Ninja Pawns.

The Terror Campaign also starring the Chancellor and Archbishop!

Starts off with the Chancellor and Archbishop but each side can drop the Terror, which is a powerful piece that can move like a queen or knight. However, the Terror cannot capture Pawns, Ninja Pawns, Knights, Bishops or Rooks.
5 ninja pawns can be dropped via an empty square in the 2nd rank.(and pushed forward optionally)

Flying Bombers Chess

The early game that started it all! Click here for details. Uses 5 ninja pawns as well.

Flying Guillotine Chess

The Flying Guillotine is a dual mode flying/jumping piece like the Flying Bomber except that it can move along diagonals as well.

Flying Guillotine vs Snake"

Here each side starts with a Flying Guillotine and a Sorcerer Snake.

Flying Guillotine vs SuperCannon

The Flying Guillotine is a dual mode flying/jumping piece like the Flying Bomber except that it can move along diagonals as well.
The Super Cannon is a combination of the Cannon in Chinese Chess and the digaonal equivalent: the Vao. Thus the Super Cannon also moves passively like a Queen, and captures using a screen both orthogonally and diagonally.

Flying Warmachines Chess

Here each side starts off with 2 Flying Elephants.
Two Flying Warmachines can be dropped via any empty space in the backrank. Dropping the Flying warwmachine counts as a turn
The Flying Elephant steps 1, jumps 2 or 3 spaces diagonally. It can move 3 spaces if there are two vacant squares or 2 pieces in-between
Similarly the Flying Warmachine steps 1, jumps 2 or 3 spaces orthogonally.

Guillotine Game

Each side starts with two Guillotines: one straight guillotine and one cross guillotine.
The straight guillotine moves 1 step up, down or sideways OR jumps 2 squares orthogonally OR jumps 3 squares diagonally.
The cross guillotine moves 1 step diagonally OR jumps 2 squares diagonally OR jumps 3 squares orthogonally.

Guillotine Vao vs War Cannon

Each side starts with a Guillotine Vao and a War Cannon
The Guillotine Vao moves/captures like a Vao or it jumps 3 squares orthogonally.
War Cannon moves/captures like a Cannon. It can also move by jumping an adjacent piece

Archer's Game

Each side starts with two Archers
The Archer may leap without capturing up to two squares in any of the three forward directions Or move one square in any of the three rearward directions or any of the three forward directions.
The Archer may shoot (capture) to any of the three forward-adjacent squares without actually moving.

Birds and Ninjas Game

Here each side starts with 2 Ninja Guards, and can drop Two Flying Bombers unto any empty space in the back rank.
See more info for Birds and Ninjas

Raptors and Birds

Here each side starts off with 2 raptors and can drop 2 Flying Bombers into the back rank.
See Raptor chess for more info