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Circe Chess is a fairy variant of chess where captures entail the immediate rebirth of the captured piece on some rebirth square.
When the rebirth square is not empty after the capture, there is no rebirth and the captured piece is removed for good. Of course, when the rebirth puts the capturing side under check, the capture is not legal.
The rebirth square is the home square for Queens. For Bishops, Rooks and Knights the rebirth is the home square having the color of the capture square. For Pawns, it is the second square on the capture file. E.g. if Wh. captures Bl. Pa4, Pa5, Ra6, Ra7, Na8, the rebirth squares would be respectively a7, a7, a8, h8, g8.
Before you ask: Of course you may castle with a reborn rook.
Fairy units are reborn too. There are two cases: when the fairy unit has a clear home square, like e.g. Nightriders used in place of Knights, it is reborn there. In other cases, like e.g. Grasshoppers, the fairy unit is seen as a promotee and is reborn on the 8th rank of the column of capture.
Here the capture & rebirth rule also applies to Kings, i.e. they may be attacked and captured as long as the home square is free. Only if the home square is occupied, a King can be checked.
Alsatian Circe is a Circe where a capture is not allowed if the resulting position is illegal under the rules of orthodox chess.
With Anti-Circe it is the capturing piece which disappears and is immediately reborn on it's home square while the captured piece is removed for good. The capture is not legal if the rebirth square is not free.
A pawn capturing on the eighth rank is first promoted and then reborn on the home square of the promoted man.
Here "checks are fairy" i.e. a King is not in check if its "capture" is not legal because the rebirth is not possible.
As Anti-Circe, but a chessman is not allowed to capture on its home square.
Juraj Lörinc wrote:
"Atom Circe is Circe with added feature that all pieces (friendly, enemy) from the squares adjacent to the square where the capture occurred, are moved to their Circe rebirth squares. Example: W Ka3, Qc3, pd3, pc2 B Kf7, Be2, Ne5, pe4, e7 If black captures Nxd3 then the following changes are made in the position:
BNe5 -> d3 (move), Wpd3 -> d2 (circe), WQc3 -> d1 (atom), BBe2 -> c8 (atom), Bpe4 -> out (atom), Wpc2 -> out (atom)
I don't know, how is it with Kings - my terminology says nothing about Kings near capture..." Now I'll gladly update this entry if anyone can help.
(Assassin is french for murderer. Is there an accepted English name for this genre?)
Here rebirth takes place even if the rebirth square is occupied. And then the occupying unit disappears for good. (Hence a unit on its home square cannot be removed.)
Here units that are seen as promoted units (by a retrograde analysis, or because the promotion occurs during the solution) are reborn as promotees, i.e. on the 8th square of the column of capture.
Martian Circe was invented by R. J. Millour in 1980. Here captures are made by first "resurrecting" the capturing unit on its home square, then letting it perform the capture. The captured piece disappears for good. (Non-captures moves are standard.)
8950 - René J. Millour
Die Schwalbe Heft 154, 08/1995
2+3. Last 6 single moves? (Martian Circe)
The bK could only reach e1 when Wh. removed some Wh. unit occupying e1 (thus giving check through the wK). Now Bl. cannot retract Ke1.
The bK is in check (from Rb8). Last moves are -1. b7-b8=R a5-a4 -2. Ka7-a6! a6-a5 -3. b6-b7 b2(b7)xBa6 and Wh. may retract B..(f1)xN/Q/Ba6.
The bPb2 may not retract anything as long as wPb6 is behind it. Indeed Wh. must drive Pb6 back to b3 so that a/cxb3 can be undone.
("Parrain" is French for Godfather.) Here captured units are reborn on a square which depends on the move following the capture (hence a move by a unit of same color, called the godfather unit). The step from the capture square to the rebirth square is given by (is equipollent to) the godfather-move. Rebirth only occurs if the rebirth-square is empty. Pawns may be reborn anywhere: on the 8th rank they are promoted, on the 1st rank they may only make a single move. If the godfather move is castling, then the rebirth-move is a King move followed by a Rook move (so that O-O as godfather-move usually leads to an occupied square :-).
While in Circe Parrain the rebirth is after the next move, in Circe Equipollents the rebirth is on the same move.
In strict circe captures are only legal if the rebirth square is empty. [Technically, this implies all strict circe problems should have all 32 pieces. Could anyone give me the exact rules for problems with less pieces?]
In Platzwechselcirce the captured piece is reborn on the square the capturing man just left. [Since this square is always empty, PWC implies that there should be 32 pieces on the board. Could anyone give me the exact rules for problems with less pieces?]
In vulcan circe, captured pieces are placed "under" a piece, occupying the rebirthsquare, and they appear again once the occupying piece leaves that square again. Example: A game could start like 1. d2-d4 e7-e5 2. Bc1-d2 e5xd4 3.Nb1-c3 d4xc3 4. Ng1-f3 [+wNg1] c3xb2 5. Bd2-c3 [+wPd2] b2-b1=B [+wPb2].
In vulcan anti-circe, the capturing piece is reborn, possibly "under" a piece occupying its homesquare (therefore the rule that the rebirth square must be empty is void).
A piece is born on the square which is on a distance of (4,4) from the capture square. There is always exactly one square on this distance.
The captured piece is reborn, the capturing piece disappears.
A piece is reborn on the rebirth square of the capturing piece. If a pawn is reborn on the promotion rank, it promotes. If the rebirth square is occupied, the piece is removed.
Circe Clone: A captured unit changes into a piece of the same kind as the capturing unit (without changing colour) and is then reborn on the game array square of the new piece, according to normal Circe rules. If the rebirth square is occupied, the captured unit vanishes. When a promotion by capture occurs, the captured unit does not change into the promoted piece but into a pawn and is then reborn in the same way it would be reborn after any other pawn capture. In case the capturing unit is a king, normal circe applies.
When a piece is captured, it's reborn on its normal Circe rebirth square, and on the square that lies mirrored in the vertical line between the d- and e-file (e.g. a black pawn captured on c3 is reborn on both c7 and f7).