Betza's funny notation ones. The notation is based on dividing moves that can be made on a board of squares into groups of symmetry-equivalent moves, the moves within a group differing only in the direction in which the step is taken. Each such group (referred to as "atom") is indicated by a capital, such as N for the 8 moves of the knight. The letter that represents the atom is usually the first letter of the simplest piece from current or historic chess variants that has this move, such as A and F for the alfil and ferz of shatranj (ancient Arabic/Persian chess).
Fairy chess piece Pieces invented for use in chess variants rather than problems sometimes instead have special icons designed for them, but with some exceptions (the princess, empress, and occasionally amazon), many of these are not used beyond the individual games they were invented for. Today's chess exists because of variations someone made to the rules of an earlier version of the game. For example, the queen we use today was once able to move only a single square in a diagonal direction, a "ferz". Today, this piece still starts next to the king, but has gained new movement and became today's queen.