Circe

Circe is a fairy chess condition, an added rule that changes normal chess. When a unit is captured, it does not always leave the board permanently: in standard Circe it is immediately reborn on a home square assigned to a unit of its type and color.

How the rebirth square is found

• A captured White queen returns to d1, the square where column d meets the first row, and a Black queen returns to d8, on the same column and the eighth row.
• A rook, bishop, or knight returns to the original square for that piece that has the same light or dark color as the capture square.
• A pawn returns to its original second row if it is White, or its original seventh row if it is Black, in the same vertical column where the capture occurred.
• If the rebirth square is occupied, the captured unit disappears as in normal chess. Kings do not take part in standard Circe rebirth.

Rebirth is part of the capture, so it can immediately alter checks, defenses, and distant lines. A capture that looks legal in ordinary chess may be illegal if the reborn unit checks the capturing side's king. To verify mate in Circe, examine both the capture square and the rebirth square.

Many Circe variants use different rebirth rules. When a composition simply states Circe, the standard form described here is normally intended. A fairy piece such as the Grasshopper is a separate idea: it changes how a unit moves, while Circe changes what follows a capture.