A.Buchanan: Tried some experiments to see if other formats of position entry are possible, but having reverted those, the solution animation no longer works. The usual PDB problem of hidden & undocumented variables between stipulation, diagrams & solution animation, sigh. (2021-04-01)
A.Buchanan: I found a "fix" - I added a bogus empty diagram b! How random! (2021-04-02)
A.Buchanan: For h#, I run Popeye without opti noca, so can see all the retro tries explicitly. For d#, I would apply opti noca if relevant, else lines of play might be blocked (2021-04-04)
Jan Hein Verduin: Composer is Johannes J. Burbach, and not Awerbach (2021-03-31, hidden)
hpr: Fixed (2021-03-31, hidden)
A.Buchanan: Have reported this to Gerd - I hope he can correct the infuriating internal state, which even the "recalculate solution" button is useless to repair... (2021-04-02, hidden)
Henrik Juel: C+ Popeye 4.61 also (with 'opt noc h1') (2021-04-03, hidden) more ...
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Henrik Juel: In b) White may not castle, because last move was done by Ke1 or Th1 (2023-12-02)
A.Buchanan: Cute. Do wPe2 & bPe3 serve any purpose, however? (2023-12-03)
Henrik Juel: C+ Popeye 4.61 (2023-12-02, hidden) more ...
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Joost de Heer: Correct solution, wrong reasoning. Castling is impossible because, if black can still castle, the diagram position is draw due to the 50-move rule! The 50 white moves are: 34 by wK (screens on c8 [with careful step on a2 to let bB pass] then g8), 11 by wB6 (to e3 to exchange place with bB then screen on a7), 3 by wR (promotion on h8), 2 by wBa4 (Ba6-b5-a4). (2003-08-31, hidden)
Henrik Juel: This problem was awarded a Special prize in the 2001 retros award, appearing belatedly in 12/2010 p.220-227 (2019-11-17, hidden)
Henrik Juel: C+ Popeye 4.61 (also) (2020-10-09, hidden) more ...
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hans: a) 1. Ke5 Td1 (0-0-0?) 2. f5 Lxg7# b) 1. 0-0-0! Dd8 2. Dxd1#
Some comment: The composer shows how important a tempo can be. Masterly accomplished! (HM). A very intensive study is needed to find the solutions: in fact not the solutions but the motivation. Has cost me days to solve this fine, extremely difficult and profound problem. In (a) 0-0-0 is not allowed., in (b) it is. In my opinion a 1st Prize Retros 2006 (GHB)

R: -1. … Dd8-b8 -2. a5-a6 Kf6-f5 -3. a4-a5 Ke7-f6 -4. a3-a4 Ke8-e7 -5. a2-a3 Lh2-g1 -6. h7-h8=L Ld6-h2 -7. h6-h7 Lf8-d6 -8. h5-h6 e7-e6 -9. h4-h5 Le6-c4 -10. h3-h4 Lc8-e6 -11. h2-h3 d7xDc6 -12. Dc5-c6 f5xSe4 -13. c6xb7 g6xTf5 -14. d5xTc6 etc.
bCap: axbxc2-c1, dxc6, hxg6xf5xe4, wCap: dxe3, gxf3xe4xd5xc6xb7, (2013-08-30)
hans: *2. Kc1-b1 (2013-08-30)
Mario Richter: I've found a cook for a), based on the idea to unpromote the black queen on c1 (shielded by the black bishop c4 on d1). The following PG shows, that the position can be reached with White still able to castle queenside:
1.Ng1-f3 a7-a6 2.Nb1-a3 a6-a5 3.Na3-c4 Ra8-a6 4.Rh1-g1 Ra6-f6 5.Nf3-h4 Rf6-f3 6.Nh4-g6 h7xg6 7.g2xf3 Ng8-f6 8.Bf1-h3 Nf6-e4 9.f3xe4 Nb8-c6 10.Bh3-f5 Nc6-b4 11.Rg1-g4 Nb4-d5 12.e4xd5 Rh8-h3 13.Rg4-e4 Rh3-c3 14.Nc4-e5 Rc3-c6 15.d5xc6 g6xf5 16.c6xb7 f5xe4 17.Ne5-c6 d7xc6 18.h2-h3 Qd8-d4 19.h3-h4 Qd4-e3 20.d2xe3 Bc8-e6 21.Bc1-d2 Be6-b3 22.Bd2-b4 a5xb4 23.Qd1-c1 e7-e6 24.Qc1-d1 Ke8-e7 25.Qd1-c1 Ke7-f6 26.Qc1-d1 Kf6-f5 27.Qd1-c1 Bf8-d6 28.Qc1-d1 Bd6-h2 29.c2-c3 Bh2-g1 30.Qd1-c1 Bb3-d1 31.Qc1-d2 b4-b3 32.Qd2-c2 b3xc2 33.h4-h5 c2-c1Q 34.h5-h6 Qc1-c2 35.h6-h7 Qc2-a4 36.h7-h8B Qa4-a8 37.a2-a3 Qa8-b8 38.a3-a4 Bd1-b3 39.a4-a5 Bb3-c4 40.a5-a6 (and now) Kf5-e5 43.0-0-0! (still possible!) f7-f5 44.Bh8xg7# (2013-08-31)
Henrik Juel: Nicely found, Mario.
So it was fortunate that the problem was not awarded in the tourney, despite the enthusiastic solver comments (2013-08-31)
Henrik Juel: According to judge Bernd Gräfrath, he did not see the cook and awarded the problem 1st-2nd prize (2013-09-01)
A.Buchanan: Was Thierry made aware of the cook? Did this ever get fixed? (2021-06-29)
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