Chess Problem - Example Problem

Example Problem

To the right is a directmate problem composed by Thomas Taverner in 1881.

The key move is Rh1. This is difficult to find because it makes no threat – instead, it puts Black in zugzwang, a situation in which every move leads to a disadvantage, yet the player must move. Each of Black's nineteen legal replies allows an immediate mate. For example, if Black defends with 1...Bxh7, the d5 square is no longer guarded, and White mates with 2.Nd5#. Or if Black plays 1...Re5, Black blocks that escape square for its king allowing 2.Qg4#. Yet if Black could only pass (i.e., make no move at all), White would have no way to mate on its second move.

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 interferences. The theme this problem exhibits is precisely such Grimshaw interferences.