Jan-Mar 2009

R338c -

(This problem was later found to be cooked)

16+15. Proof game in 14.0 moves (Sentinelles)

[rn1q1b1r/4k3/4P3/1P1P4/2b4P/1p1p1p1p/pPpPpPpP/RNBQKBNR]

Solution

Intention: 1. a4 b5 2. ab5 d5 3. Ra7 Bh3 4. Rc7 e6 5. Rf7 Bg2[Ph3] 6. Rg7[Pf7] Ke7 7. Rh7 Bf3[Pg2] 8. Rh4 Be2[Pf3] 9. Ra4[Ph4] Bc4[Pe2] 10. Ra1 Ba2[Pc4] 11. fg8=B Bb3[Pa2] 12. Be6 Bc2[Pb3] 13. Bd5[Pe6] Bd3[Pc2] 14. Bc4[Pd5] Bc4[Pd3]

Cook (found by Eddy van Beers): 9. Ra4[Ph4] Bd3[Pe2] 10. Ra1 Ra2 11. fg8=B Ra8[Pa2] 12. Be6 Bc2[Pd3] 13. Bd5[Pe6] Bb3[Pc2] 14. Bc4[Pd5] Bc4[Pb3]

R349 -

13+15. Proof game in 18.5 moves (C+)

[1nbqkbQr/p1ppp2p/1p4pp/3R2B1/8/4PN2/PPP2KPP/RNn5]

Solution

1. f4 Nf6 2. f5 Ne4 3. f6 Nxd2 4. Kf2 Nb3 5. Qd2 b6 6. Qh6 gxh6 7. Bg5 Bg7 8. e3 O-O 9. Bd3 Kh8 10. Bg6 fxg6 11. f7 Rg8 12. f8=Q Nc1 13. Qf3 Re8 14. Qxa8 Kg8 15. Nf3 Kf7 16. Rd1 Rh8 17. Qd5+ Ke8 18. Qg8+ Bf8 19. Rd5

Switchback (Bf8), Phoenix (wQ), Lois theme (Ke8/Rh8)

R350 -

Dedicated to Andrei Frolkin and Dimitry Pronkin

12+14. Proof game in 31.5 moves (C+)

[q3n3/1pp5/2pr2r1/1pb1n2b/5k2/1b5n/1PPP2P1/RNBQKBNR]

Solution

1. e4 a6 2. Bb5 axb5 3. h4 Ra6 4. h5 Rg6 5. h6 Nf6 6. hxg7 h5 7. a4 h4 8. a5 h3 9. a6 h2 10. a7 hxg1=N 11. Ra6 Nh3 12. Rc6 dxc6 13. e5 Kd7 14. e6+ Kd6 15. exf7 e5 16. f4 e4 17. f5 Ke5 18. g8=B Bc5 19. f8=N e3 20. Bc4 Be6 21. a8=R Nbd7 22. Ra1 Qa8 23. Nh7 Rd8 24. Bf1 Ne8 25. f6 e2 26. f7 exd1=B 27. f8=Q Bh5 28. Qf3 Bb3 29. Qd1 Kf4 30. Ng5 Ne5 31. Nf3 Rdd6 32. Ng1

Pronkin AUW by one side.

R351 -

12+14. Legal position?

[8/1p5p/5p1P/PP1P3p/kr1rP3/BbKpp3/Np2RP2/qNnRb3]

Solution

Last move was either d2xc1 or d2xe1. So the black pawns captured all missing white pieces. The missing black pieces were captured by the pawns on d5 and e4, which cross-captured on these squares. Both squares are white, so Be1 is the original bishop, so the last move was d2xc1=S. The white c- and g-pawn promoted without capture, so black can't take back g6xh5 and cxd early. The position is released by bringing the white knights to a1 and a2, then black retracts Ka3 and Ra4, and the knight can escape through the hole on b4.

Try: -1... d2xQc1=S? -2. Qc2-c1 f7-f6 -3. Sc1-a2 Bc4-b3 -4. Sb3-c1+ Qa2-a1 -5. Rc1-d1 Qa1-a2 -6. Qd1-c2 Qa2-a1 -7. Rc2-c1 Qa1-a2 -8. Qc1-d1 Qa2-a1 -9. Sa1-b3 b3-b2 -10. Bb2-a3 and the black king is retro-trapped on a4.

Other try: -8. Sc1-b3 b3-b2 and the black queen is on the wrong square.

Solution: Last move was d2xRc1=S! Start from the following position:
8/1p3ppp/7P/PP1P2PB/1rbrP3/kpBpp3/2RpRP2/SKRqb3 (14+14) and play forward:

1. Bb2+ Ka4 2. Ba3 g6 3. Kb2 gxh5 4. Rb1 Qc1+ 5. Kc3 Qd1 6. Rbb2 Qc1 7. g6 Qd1 8. g7 Qc1 9. g8=N Qb1 10. Ne7 Qa2 11. Rc1 Qb1 12. Rd1 Qc1+ 13. Rc2 Qb1 14. Bc1 Qa2 15. Rb2 Ka3 16. Nc6 Ra4 17. Nb4 Qb1 18. Na2 Rb4 19. Rc2+ Ka4 20. Bb2 Qc1 21. Ba3 Qb1 22. Rb2 Qc1+ 23. Nc2 Qa1 24. Nc1 Qa2 25. Rb1 Qa1+ 26. Bb2 Qa2 27. Ba1 Qa3 28. Rb2 Qa2 29. Na3 Qb1 30. Rc2 Qa2 31. Bb2 Qa1 32. Nb1 Qa2 33. Ba3 b2 34. Nb3 f6 35. Nc1 Qa1 36. Na2 Bb3 37. Rcc1 dxc1=N+