For the uninitiated, Calvinball is a brilliant creation of Calvin in Bill Watterson’s delightful comic strip Calvin and Hobbes. In the Calvin and Hobbes Tenth Anniversary book, Watterson says of the game: "People have asked how to play Calvinball. It's pretty simple; you make up the rules as you go." Applying this doctrine to chess one night led to the following game:

1) All pieces move in standard chess style and in the direction away from the player controlling them.

2) Before the game, one player places as few or as many pieces as they want anywhere on the board, within the following restrictions: neither king may be put in a situation where checkmate is possible in less than five moves (a game where this occurs is ruled a misgame), every piece on the board could be captured in one move by at least one other piece.

3) Once the board is set up, the player who arranged it flips a coin which is then called by the other player. If the other player guesses correctly, they get to choose the side they play.

4) White, as in regular chess, goes first.

5) Pawns, unlike regular chess, where they can become any piece that you want if they reach the far end of the board, can only be turned into pieces that you have had captured. Note that this excludes pieces that were never on the board.

6) Every ten turns (a turn comprising a move by one player and then the other), the board rotates clockwise by ninety degrees.

7) The objective, as in chess, is to checkmate the enemy king.

8) In true Calvinball style, any rule that both players agree to can be introduced at any point in the game. Some examples of new rules include:

A) Any piece that enters a particular area changes into a different piece. (Ie. Any piece crossing a particular line becomes a pawn.)

B) Each player chooses a random ‘teleportation square’ which they note on a sheet of paper hidden from the other player and a ‘destination square.’ If the opposing player moves any piece into that square, the note is revealed and the piece is taken to the appropriate space. A new set of squares is then chosen.

But why would anyone want to play such a game?

Standard chess, while capable of being a lot of fun, simply fails to remain interesting after more than about five games. Indeed, a progressively greater level of boredom, and perhaps inebriation as well, led to the original development of these variant rules. As it stands, chess evaluates strategic thinking and intelligence, it does a far worse job, however, of assessing creativity. This flaw is largely corrected by chess in the style of Calvinball. Remember, after all, that the above rules are more an example of the kind of thinking that goes into such a game. As Calvin himself says, the only real rule of Calvinball is that you can never play it the same way twice.