Die Schwalbe

1 problem(s) found in 1297 milliseconds (displaying 1 problem(s)). [probid='P1192196']

1 - P1192196
Dmitri Baibikow
R421v The Problemist 03/2010
Ergänze Steine zu einem IC!
Add wRb2, wBa8, wPg6, bQb3, bBd5, bSb8.
=R 1. Sd6 Bb7 4. Sf1 Be8 5. Pf2=S Bf7 8. Pf5 Be8 9. ??? Pe7=B 10. Pf7 Pf6xB (critical position) 11. Bf8 Kf5+ 12. Pe7; White then uncaptures dxcR and unpromotes a R on h8, Black uncaptures bxc (B,Q) and hxg (Q,B). But getting from the diagram (after adding units) to the critical position, with Black to retract in both, White necessarily makes an even number of moves and Black an odd number, and neither side can change parity, so the first position is illegal. Removing bPa4 would legalise as White could change parity with Ra4. If we add bRb3 instead of bQ, then removing wPa3 would not legalise as after retracting n.Ra3+ Rb3, bRa3 could not escape to b2.
play all play one stop play next play all
Keywords: Illegal cluster
Genre: Retro
Input: Gerd Wilts, 2011-4-10
Last update: Gerd Wilts, 2011-4-10 more...
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Gerd Wilts (1)