Jul-Sep 2008

R345 -

11+14. Exact proof game in 8.5 moves (C+) [Not a shortest proof game!]

[r1bqkbnr/2pppppp/P7/8/p7/4P3/1P1P1PPP/2B1K1NR]

Solution

1. e3 a6 2. Bb5 axb5 3. c4 Rxa2 4. Nc3 Ra8 5. Ra6 bxa6 6. Qa4 bxa4 7. Nb5 axb5 8. cxb5 Na6 9. bxa6

This is not an SPG: 1. e3 a6 2. Bb5 axb5 3. c4 Rxa2 4. Na3 Rxa3 5. cxb5 Ra8 6. Ra6 Nxa6 7. bxa6 b5 8. Qa4 bxa4

R346 -

14+13. Proof game in 17.5 moves (C+)

[rn2kbn1/1p1pppp1/2R3p1/2pr4/5P2/1P6/1PPPPNP1/1NBQKR2]

Solution

1. h4 c5 2. Rh3 Qb6 3. Rg3 Qb3 4. Rg6 hxg6 5. axb3 Rh5 6. Ra6 Rd5 7. Rc6 a5 8. h5 a4 9. h6 a3 10. h7 a2 11. h8=R a1=Q 12. Rh1 Qa5 13. Rxc8+ Qd8 14. Rc6 Qc7 15. Nh3 Qh2 16. f4 Qg1 17. Nf2 Qxf1+ 18. Rxf1

A Pronkin (Qd8) captured by a Pronkin (Rh1).

R347 -

16+13. Proof game in 25.0 moves (C+)

[rnbqkbnr/1pB1pp1p/1Pp5/1RQ1R3/1K5P/1PP1P3/B1P2P1P/1N4N1]

Solution

1. a4 c6 2. a5 Qb6 3. axb6 d5 4. Ra5 Bh3 5. Rb5 a5 6. gxh3 a4 7. h4 a3 8. Nh3 a2 9. Rg1 Ra3 10. Rg5 Rc3 11. dxc3 a1=R 12. Qd4 Ra8 13. Qc5 d4 14. Bf4 d3 15. e3 d2+ 16. Ke2 d1=B+ 17. Kd3 Bg4 18. Bc7 Bc8 19. Re5 g5 20. Kc4 g4 21. Kb4 g3 22. Bc4 g2 23. Ba2 g1=Q 24. b3 Qd1 25. Ng1 Qd8

Pronkin qrb.

R348 -

13+11. Mate? (Is the position legal? If so, what was the last move?)

[8/8/p7/PPPp4/krpP4/NNKPPP2/1p2rp1P/BRqqb3]

Solution

The white pawns captured 5 times (bxc5, cxb, exd, fxe3 and gxf3), the black at least twice (exd, dxc1). The black h-pawn is also captured by a white pawn, or is still on the board as a promoted piece. So the third black capture is hxg. The black g-pawn also promoted on g1, without capture. So white can't take back g2xf3 until black unpromoted twice.

Solution: Last move was d2xQc1=Q#.

Start from 8/p2p4/k7/2P5/PPpP1S2/rp1PPP2/SRQprp1P/1KBqb3 (14+11) and play

1. b5+ Ka5 2. Nc3 Kb4 3. a5 Ra4 4. Nfd5+ Ka3 5. Ka1 Rb4 6. Nb1+ Ka4 7. Qc3 Qc2 8. Na3 Qd1 9. Rb1 Qc2 10. Bb2 Qd1 11. Nc2 Qc1 12. Ba3 Qd1 13. Qb2 Qc1 14. Qa2 Qd1 15. Kb2 Qc1+ 16. Kc3 Qd1 17. Rb2 Qb1 18. Qa1 Qa2 19. Qd1 Qb1 20. Na1 Qa2 21. Rc2 Qb1 22. Bc1 Qa2 23. Rb2 Ka3 24. Qc2 Ra4 25. Nb4 Qb1 26. Na2 Rb4 27. Qd1 Ka4 28. Nc2 Qa1 29. Na3 Qb1 30. Rc2 Qa1+ 31. Bb2 Qc1 32. Ba1 Qb1 33. Rb2 Qc1+ 34. Qc2 Qd1 35. Qb1 Qc1+ 36. Rc2 Qd1 37. Bb2 Qc1 38. Qa1 Qb1 39. Nc1 Qa2 40. Qb1 Qa1 41. Qa2 Qb1 42. Ba1 b2 43. Nb3 Qc1 44. Qb1 Qd1 45. Rc1 d6 46. Qc2 d5 47. Rb1 a6 48. Qc1 dxc1=Q#

Try: Last move was d2xRc1=Q#. Further retroplay: -2. Rc2-c1 a7-a6 -3. Sc1-b3 b3-b2 -4. Sa2-c1 Qc1-d1 -5. Bb2-a1 Qd1-c1 -6. Ra1-b1 Qb1-d1 -7. Sc1-a2 Qa2-b1 -8. Rb1-a1 Qa1-a2 -9. Sa2-c1 d6-d5 -10. Rd1-b1 Qb1-a1 -11.
Sc1-a2 Qa2-b1 -12. Ba1-b2 Qb1-a2 -13. Rb2-c2 Qa2-b1 -14. Sc2-a3 Qa3-a2 -15. Rb1-b2 Qa2-a3 -16. Bb2-a1 Qa1-a2 -17. Ba3-b2 Qa2-a1 -18. Rb2-b1 Qa1-a2 -19. Sa2-c1 Qc1-a1 -20. Sa1-c2 Qb1-c1 -21. Rc2-b2 Qc1-b1 -22. Bb2-a3 Qb1-c1 -23. Bc1-b2 Ka3-a4 -24. Rb2-c2 Ra4-b4 -25. Sb4-a2 d7-d6 -26. Sd5-b4 and black has no retro move, so the try fails on one black retro-tempo.