The Retrograde Analysis Corner
No. 125 , Apr. 1998 - SOLUTIONS
4001 - Gianni Donati
Author's intention is 1. h4 g5 2. h5 Bg7 3. Rh4 Bxb2 4. Ra4 Bxa1 5. e4 Be5 6. Qe2 Bh2 7. Qb5 Bxg1 8. Bc4 Bh2 9. d3 Bf4 10. g3 g4 11. gxf4 g3 12. f5 g2 13. Bh6 g1=B 14. f4 Bd4 15. Bb3 Bg7 16. c4 Bf8 17. Bxf8 where the only motivation for the bPg7 to promotion and back to f8 is getting captured !!
Unfortunately, this is cooked (as found by TlG) with e.g. 1. h4 g5 2. h5 Bg7 3. Rh4 Bxb2 4. Ra4 Bxa1 5. Nh3 g4 6. e4 gxh3 7. Qe2 h2 8. Qb5 h1=N 9. Bc4 Ng3 10. d3 Nf5 11. Bh6 Bg7 12. g4 Bf8 13. f4 Bg7 14. gxf5 Bf8 15. Bb3 Bg7 16. c4 Bf8 17. Bxf8
4002 - N. Plaksin and A. Zolotarev
Bl. 5 caps are -1. e7xf6, g7xf6, dxexf and bxc. Wh. caps are exd plus axb and hxg, allowing the promotions of wPa2 and wPb2 on b8, and of wPg2 and wPh2 on g8. If we assume the wBd1 did play Bf1-e2-d1, then Bl. is threatened by imminent retropat.
Hence retract
-1. f7xNe6+ B~-e5
-2. e5xNf4 N~-e6
-3. d6xQe5 e6xRd7
and bl. retropat is avoided. Further unlocking is with
(1) unpromote the two uncaptured wNs on b8, reconduct the two wPs,
(2) retract b6xQc5 (not b7xQc6 !!),
(3) retract a3xBb4 (or a5xBb6) and reconduct the bB to f8,
(4) unpromote the two uncaptured wQs on g8, reconduct the two wPs,
(5) retract g7xRf6 and d7-d6, unlocking the position. remaining cap
is hxQg.
Quadruple Ceriani-Frolkin theme with precise capture squares.
4003 - Paul Raican