Jabberwocky Chess

When Alice found a strange book written in mirror writing, she could not even imagine that the poem “Jabberwocky” was only a prologue to a much more ancient and mysterious manuscript, created in the bizarre and endless expanses of the Looking Glass...

Hidden on the withered pages of that ancient manuscript was a description of a strange and unusual game...

Jabberwocky is a fairy chess piece, represented on the chessboard by the King, moves and captures like a regular chess king, but at the end of each move it turns into a different type of chess piece, depending on the previous transformation, following the chain of transformation:

King > Pawn > Knight > Bishop > Rook > Queen > King

Thus, after moving a King, the King is transformed into a Pawn of the same color. After moving a Pawn, the Pawn becomes a Knight, and so on.

The game is played on an 8x8 chessboard.

At the beginning of the game, each player has 16 kings, located along the first two outer ranks of the chessboard, as shown in the figure below:

Players alternate turns, starting with White.

As stated above, each piece's movement is accompanied by its transformation into another piece, following the cycle of transformations:

King > Pawn > Knight > Bishop > Rook > Queen > King

All chess pieces move and capture according to the FIDE Rules of Chess, except that Pawn moves only one square forward and King can be captured like any other piece.

When the King reaches the farthest rank from its original position (the eighth for White and the first for Black), instead of being transformed into a Pawn, it must be replaced, at the player's choice, by a Queen, Rook, Bishop or Knight of the same color, which is equivalent to promoting a pawn in standard chess.

Upon reaching the last rank, the King must transform into any piece except itself or a pawn.

The same is true for the King, who ended up on the farthest rank as a result of the Queen's transformation. Its subsequent movement along the farthest rank must be accompanied by its transformation into a queen, rook, bishop or knight, at the player's choice, but not into a pawn. It can only transform into a pawn by stepping onto the adjacent rank.

When moving along the eighth rank d8 or f8, the white king must be promoted to a queen, rook, bishop or knight, at the player's choice. When stepping onto the seventh rank, the white king is promoted to a pawn, following the cycle of transformations.

There is no castling in the game.

No stalemate, check or checkmate.

Capture is mandatory. If several pieces can be captured, the player chooses any of them.

At the end of his turn, a player must have at least one King of his color on the board. If this condition is not met, then such a player loses the game.

Thus, if, for example, both players have one king left, then the player whose turn it is to move loses the game, since after making a move he will not have a king left on the chessboard.

This situation, in which a player will be left without a single king when making his next move, is called the Jabberwocky Mate.

To illustrate it, let's look at the following position:

Black to move and  mate in 2

Remember that in Jabberwocky Chess, capturing is mandatory.

Leads to victory 1. ...Rg2:

The black rook is transformed to a queen, and White has only one move 2. Rxa8:

Black is left without a king, but for him this is not yet a loss, since in order to lose, he must left without a king on his turn. This is clearly not in Black's plans - 2. ...Qxa8#:

Black has a king again. White loses, as he is left without his last royal piece, which will inevitably be turned into a pawn if it makes any move.

But what if in this position:

Black will play 2. ...Qxa2:

In this case, White would win - 3. Qxa6#:

Now Black cannot play the king - there will be no black king left on the board -  Jabberwocky Mate!

When Alice has finished reading the poem she gives her impressions:

"It seems very pretty," she said when she had finished it, "but it's rather hard to understand!" (You see she didn't like to confess, even to herself, that she couldn't make it out at all.) "Somehow it seems to fill my head with ideas—only I don't exactly know what they are!''