Blue Queen on 64 and 80

Ten years ago Jeremy Good and I discussed at Chessboard Math thread an idea from 1950s problemists journals. That is, a new piece Blue Queen that moves like Queen, cannot be captured, and belongs to both sides. There is only one Blue Queen. There may have been a game played but I cannot find it now, and there does not appear to have been a separate write-up of game rules. This Rules-set changes the condition that a player may avail the one Blue Queen, so it would be different from what Good and I settled on back then, which permitted move of Blue Queen on every turn.

Blue_Queen

Setup

Pieces

Rules

Rules of Chess apply for movements of pieces, en passant, Castling, touch move, check, checkmate.

The first role of uncapturable Blue Queen is in blocking any and all pieces and Pawns from both sides. Of course Knight is blocked only in the sense that no Knight can move to a Blue Queen square.

Play follows normal F.I.D.E. rules with these added provisions for using the extra piece, Blue Queen. Blue Queen is uncapturable by either team. A side may move the Blue Queen, moving along Bishop or Rook paths of regular Queen, only if it is activated. To have Blue Queen activated, one of one's own pieces other than Queen must attack the square Blue Queen is presently on. Neither own Queen nor Pawn can activate Blue Queen.

Furthermore, one's King is allowed to move to square adjacent to Blue Queen, thus activating it, only if the other side has not already activated the same Blue Queen as of now. That is, your King can move next to Blue Queen to activate it, but only if the Blue Queen cannot be moved by the opponent the follow-up turn. Such a contingency would in effect constitute Check/Checkmate, and so it is illegal to move one's King next to Blue Queen under activation by the other side.

When Blue Queen is in fact activated for your side upon start a turn, first Blue Queen must be moved and then follows mandatory regular move of piece or Pawn. Both sides may have activated Blue Queen at the same time, but of course when the first of them to move completes turn, the Blue Queen may be in another location, where it may or may not still be in activation. As well, moving the Blue Queen when activated is optional, instead you can just leave it where it is.

Blue Queen never captures Pawn or Knight (or on 8x10 Falcon). Blue Queen is able to capture any other opponent piece attacking her, whether Bishop, Rook or Queen. Blue Queen also figures in check and checkmate by moving adjacent to opponent King, since that King in effect attacks the Blue Queen and so is subject to capture. Blue Queen making Check of course must have own piece activating her.

The same as on 8x8, on 8x10 the pieces capturable by activated Blue Queen are Rook, Bishop and Queen also if the one to be captured in fact attacks the Blue Queen, or rather her square. And to summarize activation by side moving the Blue Queen, any of your side's pieces, N or B or R, or Falcon on 8x10, or King with the above restriction, may create activated Blue Queen; yet ordinary Queen cannot do so.

Notes

It is not that difficult to activate Blue Queen for oneself since every piece but standard Queen may do so by attacking the Blue Queen's current square. The strategy then becomes, as player continues normal development of own forces, to move the Blue where it is attacked by enemy Rook, Bishop or Queen. They (R, B, or Q) are never allowed to implement the virtual threat with actual capture of invincible Blue Queen, but do enable B. Q. to capture them if there is proper activation on the capturer's side.

Adding one piece as here, or one per side as in some other CVs, puts this Blue Queen game on 8x8 and 8x10 within genre of CVs, radically changing the dynamics, including Betza's Black Ghost, Mamra, and Chess with Promoters, and those where individual board squares have effects like Warp Point.