First prize problem by Ian Shanahan, and a comic strip
8 Nov. 2010 | by Peter Wong
The current issue of The Problemist brings welcome news of an Australian composer winning a first prize in that prestigious publication. Ian Shanahan’s problem, shown below, was placed first in a section of the 2007 Fairies tourney. This demanding work belongs to an unorthodox genre known as series-movers, and also deploys a couple of fairy pieces.
The task of “series-helpstalemate in 13” means that Black plays 13 consecutive moves to reach a position where White can deliver stalemate. White has two reflecting bishops, special pieces that possess the power to “reflect” off a board edge and continue a move at a right angle. For example, the reflecting bishop on g6 is actually attacking the pawn on b3 via the path g6-e8-a4-b3, while its sibling on f6 is pinning the queen on f2 via the path f6-h4-e1-b4. This fairy piece is capable of pinning more than one enemy piece at a time, a handy ability in a problem where stalemate is the aim.
The Problemist 2007, 1st Prize
Series-helpstalemate in 13, Reflecting bishops f6, g6
Here is the solution: 1.d4 2.Kc3 3.Kc2 4.Qe2 5.Sf4 6.Sd3 7.Rxe7 8.Rd7 9.b2 10.b1(S) 11.Rh1 12.Rd1 13.Qe7, enabling rBxe7 stalemate. Notice the unique move order of the sequence, forced by some remarkable self-pinning and unpinning effects, e.g. 3.Kc2 unpins the queen and also self-pins the h5-knight (rBg6-h5-d1-c2), so that the latter cannot move until it is unpinned by 4.Qe2.
After such a tough nut, here’s a bit of comic relief from the xkcd site!