The Problemist Supplement, 2010
Mate in 2
Maos c6, g8
Vaos d6, e4; h3
Paos c8, f1, g7
This week’s problem uses pieces developed from Chinese Chess. The Mao and Pao have equivalents in the Chinese game, while the Vao is derived from the Pao. The Mao moves like a knight, but is not a leaper. It moves first one square laterally then one diagonally; if the lateral square is occupied the Mao cannot move on. The Mao at g8 in the diagram can move to e7, but not to f6 or h6. The Pao and Vao move like a rook and bishop respectively, but to capture must jump over a hurdle. A Pao standing at a1 with a piece (of either colour) at a5 could move along the rank or to a2, a3 or a4, and capture any enemy piece which stopped at a6, a7 or a8.
(Note that the accepted notation for pao is PA) The position is a block, with mates set for all of Black’s moves: 1...Me7 2.PAh8; 1...Mc any 2.PAcc1; 1...Vxc8 2.PAf3. There is one changed mating move after the key 1.PAa1, namely 1...Vxc8 2.Vb1. A clever change, with the pao and vao exchanging checking and hurdle duties. 2.PAcc1 may be regarded as a second change, since the two paos have also exchanged roles. The black vao is unable to move to g2 after 2.PAh8 because of an antipin effect, and this is doubled after the key. There are a number of tries, the best being 1.Kg3? which gives a new mate 1...Vg4 2.Kf3 but is refuted by 1...Me7! The mao at c6 could be replaced by a knight. Normally an orthodox piece would be preferred to a fairy piece where possible, but Stephen felt that it would be more aesthetic to have a full set of fairy pieces.