Superpermutation Chess

Let's try to imagine for a moment what kind of chess representatives of other worlds could play if we showed them an ordinary chessboard and pieces...

"We have something similar on our planet, Earthling. Only all your rules that you told me are too primitive for my mind.
We will play with your pieces on this board according to our rules, which will be immediately telepathically transmitted to your head for quick assimilation."

Superpermutation Chess

The game follows the rules of Standard Chess exactly, with the following exceptions:
In this variant of chess, the pieces are deprived of the ability to make a capture. The only exception is the King. Only the King can capture the opponent's pieces.
Although all other pieces are not aggressive towards each other, they can threaten the opponent's King, as in regular chess, by declaring check or checkmate to the latter.

A player must move his King away from check and must not leave it under attack at the end of his turn.

There is no castling and en passant in the game.

Teleportation and Superpermutation

Teleportation

During the game, instead of moving the King, a player can swap it with any of his other pieces except Pawns. This is called Teleportation - the King is placed on the square where a friendly piece is standing, which in turn is moved to the board square vacated by the King.

Teleportation is not possible if the King is in check.

If as a result of Teleportation a player's King is in check, that player loses the game.

When Teleporting the King and the selected piece, the Superpermutation (see below) does not occur in the game.

Teleportation is a full and complete move.

Superpermutation

A piece that, as a result of its movement, ends up IN FRONT of any other piece standing on an adjacent square, makes a Superpermutation, changing places with it.

So in the next position:

Black plays 1. ...e7-e5:

The result of such a move will be the following position:

The black pawn makes a Superpermutation, because after completing its move, it finds itself in front of a white piece standing on the adjacent square in a vertical row, with which it changes places.

If the piece making the Superpermutation is again in front of any piece in the vertical row, then the Superpermutation continues until there is an empty square or the edge of the board in front of the piece making the Superpermutation.

For example, in the position above, White decides to play 2. Bf1-h6:

There is a Pawn in front of the Bishop vertically, so the Bishop makes a Superpermutation, changing places with it:

As a result of this Superpermutation, another piece appears in front of the Bishop again - the Rook, with which it also changes places:

Now the Superpermutation is complete since there are no more pieces in front of the Bishop.

A movement of a piece and its subsequent Superpermutation is a complete and finished move.

If check is declared, then the Superpermutation does not occur:

White made the move 3. Nd5-f6 and declared check. There is no Superpermutation in this case. The Knight cannot change places with the Pawn f7 and then with the Bishop f8 because of the declared check.

If the piece performing the Superpermutation declares check, then the Superpermutation ends immediately:

White plays b2-b4:

After which the White Pawn's Superpermutation begins:

and further:

Here the Pawn's Superpermutation is complete as it declares check to the black King.

The Superpermutation of a piece for a player is always carried out strictly upwards vertically.

A player cannot make a move with a piece that results in his King being attacked.

Here White cannot play b2-b4, since as a result of the Superpermutation, his King ends up in check.

As a result of the Superpermutation, the Pawn can end up on either the first or the last rank.

In the first case, the Pawn can make only one step to the second rank, from which, as in regular chess, it can move immediately two squares in its next turn.
In the second case, having reached the last rank, again as in regular chess, the Pawn is transformed at the player’s discretion into any piece of its color, except for the King and itself.

The game uses full algebraic notation, with final square indicated in the case of a Superpermutation. So, for the first example in the description of this chess variant, Black's move would look like this: 1. ...e7-e5-e4

Let us now turn to one of the first test games, which will illustrate everything stated above very well.

1. Nb1-c3   d7-d5
2. Ra1-b1-b2

The white rook makes a Superpermutation, and the white pawn will have to start the game from the first rank.

2. ...        Nb8-c6
3. f2-f3   e7-e5
4. Rb2-b6-b7

The rook wedges into the ranks of black pieces.

4. ...    Bf8-a3-a2

Black's bishop also makes a Superpermutation, becoming light-squared. Now Black has two light-squared bishops.

5. Nc3-b5-b7

From this position, the white knight can check the black king either from the d6 square or by jumping to c5 - as a result of the Superpermutation, it will end up on c7.

5. ...         Qd8-h4+
6. g2-g3  Qh4-h3-h1

The black queen, using Superpermutation, reaches the edge of the board on the White's half.

7. Rh2-f2-f3  Ra8-b8-b5

Both players made a Superpermutation with their rooks.

8. b1-b2  Qh1-g2-g1

The black queen is getting closer and closer to the white king.

White's next move leads them to disaster:

9. b2-b4-b8=Q

By jumping two squares forward, the white pawn finds itself immediately in front of a whole row of pieces in a vertical row, which allows it to quickly reach the last rank and turn into a queen using the Superpermutation.

It would seem that White has an advantage. But it is not so. In this position, Black checkmates in one move.

Can you find it?

There is nothing difficult about this if you know how, where and when to use the Superpermutation.

9. ...Rb4-f4-f1#

Breaking the laws of space and time, the black rook makes a Superpermutation from the f4 square, mating the white king.

I didn't remember how I ended up at home...

The angry November rain mercilessly pounded the thin glass of my window...

Memory slowly returned to me... Some kind of flying saucer, a scary alien face and a strange chess game...

Although, maybe I just imagined it all.