PWC: When a capture is made, the captured unit (except a King) is replaced on the square the capturing unit just leaves. A Pawn is immovable on its 1st rank.
AntiCirce Diagram: When a piece captures (including King), it must come back to its rebirth square (the square it occupied in the diagram position): if this square is occupied, the capture is forbidden. A Pawn capturing on its promotion rank promotes before it is reborn. (Or from Fairings No.42: As Anti-Circe except that the rebirth square for the capturing unit is the one where it stands in the diagram. In the Cheylan sub-type a capture by a unit on its own rebirth square is not allowed.)
No.1430Chris Feather England original – 04.08.2019