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The thematic approach to solving is to notice then that in the original position, black is already almost in zugzwang. If black were compelled to play first, only Re3 and Bg5 would not allow immediate mate. However, each of those two moves blocks a flight square for the black king, and once white has removed its rook from h2 white can put some other piece on that square to deliver mate: 1...Re3 2. Bh2# and 1...Bg5 2.Qh2#.
The arrangement of the black rooks and bishops, with a pair of adjacent rooks flanked by a pair of bishops, is known to problemists as [[Organ Pipes]]. This arrangement is designed to illustrate the effect of mutual black interferences: for example, consider what happens after the key if black plays 1...Bf7. White now mates with 2.Qf5#, a move which is only possible because the bishop black moved has got in the way of the rook's guard of f5 - this is known as a ''self-interference''. Similarly, if black tries 1...Rf7, this interferes with the bishop's guard of d5, allowing white to mate with Nd5#. Mutual interferences like this, between two pieces on one square, are known as [[Grimshaw (chess)|Grimshaw]] interferences. The theme this problem exhibits is precisely such Grimshaw interferences.
==Abbreviations==
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