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The Retrograde Analysis Corner

Europe Echecs

No. 441, Jan. 1996 - SOLUTIONS

613 - T. Le Gleuher
Europe Echecs 441, 01/1996

Wh. caps are c2xPb3, e2xf3 & h3xg4. Bl. caps are h2xg1=B and axb to allow bPa7 in the balance. So that we may only add a wh. unit. But the position can only be explained if we add the wKB on h3, behind bBg2 in the a2-b1-c2-d1-e2-f1-g2-h3 corridor.

Then the position is released by (1) reconducting bBg2 on b1, (2) retracting wPc2xPb3, (3) reconducting bKe1 on h3 and wBh3 on e2, (4) taking back bKh4-h3 wPg2-g3+, (5) reconducting wBd1 on f1, (6) retracting wPe2xQc3, (7) reinstalling bl. K, Q & QB in e8, d8, c8, (8) retracting b7-b6, which releases the position.

After we add +wBh3, mate in one is with 1. <whatever> Rc2#


614 - T. Le Gleuher
Europe Echecs 441, 01/1996

Wh. caps are h2xg3xf4xe5xd6xc7. Bl. caps are b7xBa6. The bPh7 has been captured on the h-file or else has been promoted on h1. In that latter case, Wh. cannot O-O. But in the former case Bl. cannot O-O.

Indeed, if the bPh7 has not been promoted, then we have to retract bPd7-d6 and wPf4xBe5xQd6xPc7, reinstall bBf8 first, Qd8 and Bc8 then, on their home squares before we can retract bPb7xBa6. But then, Bl. needs 7 waiting retro-moves before Wh. can retract g3xf4. Bl. must use his Rh8 for these waiting moves, even if we assume the bPh was captured on h2. Thus Bl. O-O is forbidden.

Conclusion: castlings are mutually exclusive and we cannot tell which is legal and which is not ! In that case, whoever castles first is allowed.

Mate in 3 is with 1. O-O!! (threat. 2. c8=Q & 3. Ne6#)
1 ... O-O?? illegal
1 ... Kd7 2. c8=Q+ Kxc8 3. Qb7#
1 ... Kf8 2. Ne6+ Ke8/g8 3. c8=Q#

The key-move has only one (pure) motivation: forbidding 1 ... O-O.


615c - M. Caillaud
Europe Echecs 452, 01/1997 (for the corrected version)

1. d3!! Nc6 2. d4 Ne5 3. dxe5 Nf6 4. exf6 Rg8 5. fxg7 f6!! 6. gxf8=N Rg3 7. hxg3 f5 8. Rh6 f4 9. Rd6 exd6 10. Ne6 Qh4 11. Nc5 Qh3 12. gxh3 h6!! 13. Bg2 h5 14. Bc6 dxc6 15. Kf1 Be6 16. Kg2 Bb3 17. axb3 O-O-O 18. Ra6 Rd7 19. Rb6 a6!! 20. Na4 a5 21. Ra6 c5 22. Ra8 mate


616c - N. Plaksine and A. Zolotarev
Europe Echecs 452, 01/1997 (for the corrected version)

It is possible to reach the position with only 2 Q moves: bQd8-a5xe5. Then the 6 bl. caps are Qa5xe5, b7xBc6, gf6, c7xd6xe5xf4 and wh. caps are hxg and axb for promotions of wPa2, b2, g2 & h2 on b8 & g8. (Bl. must not uncapture wQ's because this would increase the total number of Q moves !!)

Retract
-1. Qa5xRe5+ Rb5-e5
-2. e5xRf4 Rg4-f4+
-3. h4-h3 Rb8-b5
-4. h5-h4 b7-b8=R
-5. d6xRe5 a6xBb7
-6. Bc8-b7 Rg8-g4
-7. Bb7-c8 g7-g8=R
-8. Bc8-b7 g6-g7
-9. Bb7-c8 g5-g6
-10. Bc8-b7 h4xRg5
-11. Rg4-g5+ Rd5-e5
-12. Re4-g4 Be5-d4
-13. Rb4-e4 Rc5-d5
-14. Rb8-b4 Rb5-c5
-15. Ra8-b8 Rb8-b5
-16. Bb7-c8 h3-h4
-17. Bc8-b7 b7-b8=R
-18. Rb8-a8 b6-b7
-19. b7xRc6 and everything unlocks.

Finally, only 2 Queen moves are required, yielding four wR Ceriani promotions.


617 - A. Zolotarev
Europe Echecs 441, 01/1996

Wh. caps are b2xc3, Bc1xb2 and fxe/g for promotion of wPf2 to black-squared B. Bl. caps are a7xb6xc5 and fxe/g allowing the bPf7 to enter the balance (possibly via a promotion on e1/g1).

Retract
-1. Bc1xNb2+ Nd3-b4
-2. h5-h6 Ne1-d3
-3. h4-h5 f2xNe1=N
-4. Nd3-e1 f3-f2
-5. Nf2-d3 f4-f3
-6. Nd1-f2 Nd3-b2
-7. Nb2-d1+ Nb4-d3
-8. Bc4-a6 Na6-b4+
-9. Bg8-c4 f5-f4
-10. g7-g8=B f6-f5
-11. g6-g7 f7-f6
-12. f5xBg6 Bh5-g6
-13. f4-f5
Bg4-h5
-14. f3-f4 Bc8-g4
-15. Kb5-a5 d7xQc6+ etc.

25 last single moves are completely determined.