In Regiment Chess (also Regimentation Chess) Black can decide the initial positions of the kings, whose positions are mirrored, but only White has the option to relocate the queen. Regiment Chess is like standard chess except that the players can, before play begins, swap places of the king/queen and another piece except the rooks. Thus, when the king is swapped (relocated), the other piece (the relocatee) ends up on the king's square. When the queen is swapped, the relocatee ends up on the queen's square. One restriction is that the bishops mustn't end up on the same square colour, and the king cannot become a relocatee (i.e. swapped by the queen). Note that black begins by swapping his king. Alternatively he can choose to leave the position as it is (by pressing the king). The white player then mirrors black's swap. After the kings thus have been swapped, White can now relocate the queen, if he so wishes. Then he immediately start the game by making the first move.

Note that the king retains his castling rights even if it has been relocated. The castling rules are simple and derive from Chess960. King and rook end up on their usual squares. The only difference is that the king can make longer (or shorter) leaps than usual. All squares between king and rook must be empty and unthreatened.
Note! If the king starts the game on a castling destination square (c or g), castling on that side is done by moving the rook instead of the king.

Curtailed castling: in an alternative variant, if the king is positioned on the g or b file, castling is restricted to the side on which the king is positioned. The variant could be useful to enhance strategical predictability.