Chess Bingo (2022-05-02 v2)

# chess bingo

Developed by notEphim from Celestecord.
These rules written by me, with much of the content thanks to discussions with notEphim as to the original intent of the game.

## basic play

The two players play a series of chess games at a preägreed time control, alternating colors.
It is recommended that the time control be blitz or faster.
After each chess game, the winner gets to tick off one or more bingo objective which they have completed, subject to the rules of the bingo variant being played (see "bingo variants").
If the chess game was won on time or by resignation, in addition to ticking off any objectives they have completed, the winner also gets to tick an objective of their choice which need not have been completed, subject to the rules of the bingo variant being played (see "bingo variants").

Objectives are either cumulative (denoted by "inc" for "incremental"), or non-cumulative (sometimes marked with "in a game" if potentially ambiguöus).
Progress for cumulative objectives is kept across all chess games, and the cumulative objective in question may be ticked after any win or draw so long as the condition was previously met, even if it was met during a previous chess game.
In contrast, non-cumulative objectives must be completed within the span of a single chess game and may only be ticked directly after winning or drawing the chess game in which they were achieved, not later on.

For objectives phrased as "x checks with a piece {in a game}", the checks do not need to be delivered with the same piece.

Objectives which refer to developing a piece a certain way refer to that piece making its first move that way.
For the "Develop a rook vertically" objective, the rook may not have been involved in castling prior to developing vertically.
"Develop a bishop to the short diägonal" means either to fiänchetto it, or go one space further in the fiänchetto direction.
"Develop a knight to the second rank" means to the seventh rank if you're playing Black.

For objectives phrased as "capture all piece in a game", only the opponent's pieces of that type must be captured.
If the opponent has promoted to that piece type, the promoted piece must also be captured.
If the opponent started with no pieces of that type (due to a material handicap), unless one of their pawns later promotes to that piece type and is captured, such an objective may not be ticked that game.

For objectives requiring piece(s) to be advanced to the last rank, promoting a pawn counts towards the objective, and the pieces (if multiple) need not be on the last rank at the same time.

"Stalemate" requires that one deliver stalemate, while "Get Stalemated" requires that one be stalemated.

For objectives dealing with pieces visiting sides of the board, a pawn is considered the same piece before and after promoting, and thus can visit some required sides as a pawn, and the rest as a promoted piece.
If the objective specifies the type of piece, the visits must be on or after the promotion, though.
Corner squares count as part of both sides of the board to which they are adjacent.
Kings and Pawns count as pieces for the purposes of pieces visiting locations on the board.

Developing a piece refers to a piece's first move in a game.

## bingo variants

### 1-line

Non-lockout.
First to complete 1 bingo line wins.
If both players complete 1 bingo line simultaneously, the bingo game is a draw.

### 3-line

Non-lockout.
First to complete 3 bingo lines wins.
Lines may share objectives, but do not have to.
If both players complete 3 bingo lines simultaneously, the bingo game is a draw.

### lockout

Lockout.
First to tick 13 objectives wins.
Players may not tick the same objective.
If there is a drawn chess game, black gets to tick their objectives before white.

## chess handicaps

### material handicap

If the players' chess skills differ greatly, one player may not be able to win or draw much, if at all.
To remedy this, a handicapping system may be employed.

Before beginning play, both players agree on a "handicap value" in points to be used for the chess games.
In less formal settings, this value may be altered during the bingo game if it appears it was chosen injudiciously.
For the purposes of determining handicap, pawns are 1 point, knights and bishops are 3 points, rooks are 5 points, queens are 9 points, and kings may not be sacrificed as part of a handicap.

At the beginning of each chess game, one of the players will choose the pieces the handicap giver will start the chess game without.
Before starting the first chess game, whether playing white or black, the handicap giver chooses pieces equal to or greater in total value (as defined above) than the preägreed "handicap value" to start without, using the position editor.
The handicap giver also chooses in the same manner in the 4th and 5th chess games, the 8th and 9th chess games, the 12th and 13th chess games, and so on.
Before starting the second chess game, whether playing white or black, the handicap taker chooses pieces equal to or lesser in total value (as defined above) than the preägreed "handicap value", using the position editor.
The handicap taker also chooses in the same manner in the 3rd chess game, the 6th and 7th chess games, the 10th and 11th chess games, and so on.
There is one restriction (besides total point value) on which pieces may be chosen as part of the handicap, and it applies to both the handicap giver and the handicap taker: no more than p+1 pawns may be sacrificed as part of a handicap where p is the number of pieces sacrificed as part of that handicap, except that it is always permissible to sacrifice up to 2 pawns as part of a handicap.
Different handicaps may be chosen each chess game.
Pieces which are not sacrificed must be left in their normal positions.

The players still alternate white and black, which will result in both players getting chances to play as both colors while choosing the handicap which the handicap giver uses.

### time handicap

Material handicaps may change the character of the game of chess too much for some players' tastes.
As an alternative, time handicaps may be used, in which the handicap giver plays with a faster time control than the weaker player.
This is, unfortunately, not supported by [lichess](lichess.org), but for fairly short time controls (about bullet or faster) the handicap giver may simply wait for their clock to tick down to a preägreed value before playing their second move (players' clocks do not start until after they have played their first move, on lichess).

## bingo handicaps

If the players' chess skills are closer, to the point where they can both win the chess games a fair proportion of the time, a more subtle handicapping scheme may be desired.
When playing lockout, changing the target goal to more than 13 objectives for the handicap giver (and correspondingly less for the handicap taker) may be elegant.
When playing 1-line or 3-line, requiring the handicap giver to make more bingo lines (and/or the handicap taker to make fewer) may be elegant.