Circe File: Captured figures (not Ks) reappear on the 1st (8th) rank of that file, where they have been captured. Pawns reappear on their game-array squares on the file of capture.

Disparate PY: If one side makes a move with a piece of type “x” (black, white, neutral, half-neutral, etc., King included), the other side cannot answer immediately by moving a piece of the same type “x”. (For example: white Qc1, black Ka8,Qa7 – mate in 1 move. After 1.Qc8#, Black is mated because 1…Qb8? is illegal. The mate is possible also with the neutral nQc1 – after 1.nQc8#. Black cannot move the same neutral Queen.) Every Pawn’s promotion is a Pawn’s move, therefore after such promotion (into any possible piece) the other side cannot answer immediately with its Pawn. We can say that after the move of the figure of type “x” any enemy figure of type “x” falls under Half-moving paralysis. This paralysis disappears immediately on the next half-move, if the opponent plays with another piece of type “y”. (“Disparate PY” is implemented as “Disparate” till the latest version of Popeye, PY 4.73. In WinChloe this version of Disparate is available starting version 3.33.)

Circe Equipollents: After a piece is captured, it is immediately replaced on the square which is the same distance and direction from the square of its capture, as was that square from the square upon which its captor commenced its move. (If Qf7 captures a Pawn on e7, it is reborn on d7, because d7 is a same distance and direction from e7 as e7 is from f7. Similarly, if Qg7 captures a piece on ‘e7’ its rebirth square is ‘c7’). If the rebirth square is occupied the captured piece disappears. Castling with replaced Rook is permitted. Pawns may be reborn on the 1st and 8th ranks. Pawns reborn on the 8th rank are promoted as part of rebirth and the promotion is chosen by the player who makes the capture, i.e., if White captures a black Pawn, and the black Pawn is reborn on the 8th rank, White (not Black) decides what Black’s Pawn will be promoted to. Pawns reborn on the 1st or 8th rank can make only one-square move (for example black Pc8 can play only on c7 or it can capture an enemy units on ‘b7’ or ‘d7’). During the en passant capture, the Pawn is replaced on the rank opposite of the captor. For example, if Black moves c7-c5, White Pawn on ‘b5’ captures en passant, moves to ‘c6’, while the black Pawn is reborn on ‘d6’.

Alphabetic Chess: The squares are considered in the order a1, a2…a8, b1…b8, c1 and so on to h8. At each turn, only the unit standing on the square which comes earliest in this order may move. However check and mate are normal.

Berolina Pawn(BP): Walk and capture are swapped relative to the orthodox Pawn. The Berolina-Pawn moves without capturing diagonally (possibly two squares if it is on the second row of its side) and captures vertically.