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This week, we return to the realm of the orthodox direct twomover, with another
prize-winning effort by the great Indonesian composer. No clues this week!
To appreciate the problem, one must first consider the try 1.Qd5?, which threatens
2.Qxf5#. Now the two bK moves 1...Kg5 and 1...Kf6 run into the mates 2.Rg2# and 2.Se4#
respectively. However, Black has the refutation 1...Sd4!.
Instead, the key is 1.Qf3! with the same threat as after the try, and the same two
thematic bK move defences. However, what we see now is that the mating moves which
followed the bK flights in the try-phase are swapped over – now 1...Kf6 is met by
2.Rg2# and 1...Kg5 by 2.Se4#. We thus have a case of reciprocal change. Note that the
try-refutation 1...Sd4 now fails to 2.Rg2#, since the wQ guards f6, whilst other
bS-moves fail to 2.Se4 or 2.Rg2.
Any comments or questions on this problem should be addressed to
Steve Giddins (our Libarian and Archivist) using the 'Contact'
item in the menu on the left.