[Retros] Christmas puzzles of Stuttgarter Zeitung - solutions

[keilhack at aol.com]

The theme of this years Christmas puzzles - delayeddue to the coverage of the WCh match - is Chess960, or Fischerrandom chess. Forour purposes, it's not the basic position decided by lot which is relevant forus, but the special castling rules and it's possibilities for problem chess. Asalways the puzzles had been selected by Werner Keym.
In Chess960, in the starting position the kings are placed somewhere betweenthe rooks. And as long as king and rook had not moved, long and short castlingis possible, whereafter it's - as usual - Kg1/Rf1 or Kc1/Rd1 (for White).
A special feature here for retro problems is, that the solver has an unusualwide choice when positioning king and rook after retracting castling.
As every year, the solver has to check whether there is more than one possiblesolution.

Werner Keym, original. White mates in three moves, Chess960

r4kr1/p1p5/5K2/8/8/3Q4/8/8w - - 0 1

Solution:
First solution: 1.Qa3+ c5 2.Qxc5+ Ke8 3.Qe7#. Second solution: As Blackjust made a move, only one of the two castlings is still possible (so called „partialretroanalysis“). If ...0-0-0 is still possible, then 1.Qd7! (but not 1.Qh7?0-0-0!) 1...Rg6+ 2.Kxg6 resp. 1...Rg7 2.Qxg7+ followed by mate. If 1...0-0 ispossible, now 1.Qh7! (1.Qd7? 0-0+!) 1...Rg6+ 2.Qxg6 resp. 1...Rg7 2.Qxg7+. Thissecond solution consists of two excluding partial solutions.


Werner Keym, Problem-Schach-Kunst 2024
White retracts one move and then mates in two moves, Chess 960
7k/8/8/5B2/8/4p3/8/4RRK1 b - - 0 1

Solution: retract 0-0 (king to f1, rook to g1) and now 1.0-0-0 (king toc1, rook to d1) 1...e2 2.Rd8#.

Bernd Graefrath, Koenig & Turm 2002 (revised version)
Whiteretracts one move and then mates in two moves, Chess 960
8/8/8/8/2P5/6k1/8/2KR3R b - - 0 1

Two solutions: retract Rd4-d1 and now 1.0-0 (Kg1, Rf1) 1...Kh3 2.Rf3#. Aswell as retract 1.0-0-0 (Kf1 and Rd1 unchanged) with 1.Rd4 Kf3 2.Rh3#.

Regards, Harald Keilhack

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