No.871 by Rainer Kuhn & Franz Pachl – Rich strategy with final moves by half-neutral piece, previously shown by Franz Pachl in the problems for the 1^st Riga Black Balsam TT. (JV)

Definitions:

Half-neutral piece: Piece which can exist in black, white or neutral state and changes its state by the rules:

• A piece in the neutral state may be moved by Black or White, and after move it changes into black or white state respectively.
• A piece in the white state may be moved only by White, and after move it changes into its neutral state.
• A piece in the black state may be moved only by Black, and after move it changes into its neutral state.
• Only a half-neutral pawn can promote into half-neutral figure.

Additional features of half-neutral pieces:

• Castling with half-neutral King is possible with hK in white phase on e1 (White castling) and hK in black phase on e8 (Black castling). After castling the hK becomes half-neutral phase and can become mate.
• A play is possible also with only one half-neutral King on the board (in white, black or neutral phase).
• By the notation: “h”=half-neutral piece, states are marked with “w”(white), “b”(black) and “n”(neutral).

Nightrider(N): (1,2) Rider. Operates along straight lines with squares lying a Knight’s move away from each other.