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Oct1218   WorstPlayerEver: Very nice, although 44. Rf1 wins also. 

Oct1218
  patzer2: Didn't see Geller's clever 44. R4f5! + (+7.68 @ 30 ply, Stockfish 9) as a solution to today's Friday puzzle. Instead, I went with 44. Qf2 as Geller did when he first visualized this position after 41...Kh7 and played 42. Qf2. Geller apparently thought repeating the position with 44. Qf2 Kg7 goes nowhere, since after 42. Qf2 Kg7 he regrouped and came up with 43. Qb2 Kh7 44. R4f5! + (+7.68 @ 30 ply, Stockfish 9). When I plugged it into the computer, I also thought 44. Qf2 Kg7 doesn't go anywhere. Because immediately after 43...Kh7, the Stockfish 9 evaluation of 44. Qf2 Kg7 = (0.00 @ 39 ply) is an assessment of equality. However, When I forced the program to reassess the position one move later (i.e. after 44. Qf2 Kg7), Stockfish 9 found a win in Geller's abandoned line with 44. Qf2 Kg7 45. Kg2! + (+7.61 @ 31 ply). Here is White's won position after 44. Qf2 Kg7 45. Kg2! (diagram below) click for larger viewOne winning possibility here (diagram above) is 45...Bb7 46. g4! hxg4 47. h5 gxh5 48. Qe3 + (diagram below) click for larger viewwith the decisive mate threat (i.e. 48...Ba8 49. Rxg4+ hxg4 50. Qh6+ Kg8 51. Rg6#). P.S.: So where did Black go wrong?
The second player's game took a turn for the worse with 26...Nfd7, allowing White to build a strong attack with 27. Rf2 ± (+0.84 @ 32 ply, Stockfish 9). Instead, Black would've had better drawing chances with 26...Ned7 27. e5 Nxe5 28. Nxe5 Rxe5 29. Ng4 Nxg4 30. Qxf7+ Kh8 31. hxg4 Qc6 ⩲ (+0.62 @ 41 ply, Stockfish 9). Earlier, he could have secured a fully level position with 25...Nh5 Qf6 27. Neg5 Nxg4 28. Nxg4 Qd4+ 29. Nf2 Rc8 ⩱ to = (0.19 @ 33 ply, Stockfish 9). 

Oct1218
  gofer: <44 R4f5 ...>
Black cannot accept...
44 ... gxf5???
45 Rh6+!! Kxh6
46 Qh8+ Kg6
47 exf5+ Kxf5
48 Qxh5+ Kf6
49 Qg5#
Black cannot refuse by moving the king...
44 ... Kg7/Kg8/Kh8 mate in two
44 ... Kh6? 45 Rxh5+ Kxh5 (Kg7 Rxf7++ mating next) 46 Rf5+ gxf5 47 Qf6! mating after 5? spite checks Black cannot move either rook...
44 ... Rxe4
45 dxe4 +
44 ... Rd8/Rd6/Rd5/Rd4/Rxe4/Re8/Re6/Re5/Rxe4
45 Rxf7+ Rxf7
46 Rxf7 Qxf7
47 Bxf7 +
Black cannot move the Bishop or play some Queen moves 44 ... Bb7/Ba6/Qa7/Qb7
45 Rxh5+ gxh5 (or mate in two with Kg7 Rxf7+ mating or Kg8 Rxf6+ mating)
46 Qd2! + (threatening 47 Qh6+ Kg8 48 Rg6#)
In all the above scenarios, it looks like black will have to give up a rook and queen to avoid mate. Meaning moving into
a Q+B v R+B endgame...
Perhaps the most interesting defence is...
<44 ... Qd8>
45 Rxh5+ no longer seems to work, so simply picking up Pc5 may be enough to tip the balance permanently in white's favour! ~~~
Yep. Black walked in the trap with arms open wide... 

Oct1218
  gofer: Actually, it looks like 45 Bxf7 is a huge threat if black plays 44 ... Qb8 or 44 ... Qd8. So between Rxf7+, Bxf7 and Rxh5+ black is stuffed!!! 

Oct1218
  agb2002: White can attack the black king with the maneuver 44.R4f5 followed by Qd2 or 45.Rxh5+ and Qd2: A) 44... gxf5 45.Qd2
A.1) 45... Rd6 46.Qh6+ Kg8 47.Rxd6 (threatens 48.Rg6#) A.1.a) 47... Be6 48.Bxe6
A.1.a.i) 48... Qxd6 49.Bxf7+ and 50.Qxd6 +  [Q+P vs r]. A.1.a.ii) 48... Rxe6 49.Rxe6 fxe6 50.Qxe6+ wins two pawns (50... Qf7 51.Qxf5 Qxf5 52.exf5 Kf7 53.g4 hxg4 54.Kg3 Kf6 55.Kxg4 wins). A.1.a.iii) 48... fxe6 49.Rxe6 fxe4 (49... Rxe6 50.Qxe6+ transposes to A.1.a.ii) 50.Qg6+ Kf8 51.Qxe4 wins a pawn at least. A.1.b) 47... Be6 48.Rxe6 fxe6 (48... Rxe6 49.Bxe6 fxe6 50.Qe6+ as above) 49.Bxe6+ Rf7 50.exf5 is probably simpler than A.1.a. A.1.c) 47... Re6 48.Bxe6 Bxe6 (48... Qxd6 49.Bxf7+ as in A.1.a.i) 49.Qg5+ followed by Rd8 wins. A.2) 45... Re6 46.Qh6+ Kg8 47.Bxe6 wins due to 48.Rg6# (47... fxe6 48.Rf8#). A.3) 45... Kg7(8) 46.Qg5+ Kf8 (46... Kh7(8) 47.Rh6#) 47.Qh6+ Ke8 (47... Kg8 48.Rg6#) 48.Qh8#. B) 44... Bb7 45.Rxh5+ gxh5 (45... Kg7 46.Rxf7+ Kg8 47.Q(R)h8#; 45... Kg8 46.Rxg6+ Kf8 Q(R)h8#) 46.Qd2 as above. 

Oct1218
  agb2002: I missed 45... f4 which seems to win for Black. Better luck tomorrow. 

Oct1218
  Carlos0012358: Black is behind the eight ball anyhow, but 44........gxf5 is an absolutely inexcusable move. 

Oct1218   5hrsolver: if <44 ... Qd8> One line is:
44. R4f5 Qd8 45. Bxf7 gxf5 46. Rh6+ Kxh6 47. Qf6+ Kh7 48. Qg6+ Kh8 49. Qh6# 

Oct1218   TheaN: Friday 12 October 2018
<44.?>
I was keen on making Rxg6 work but completely missed <44.Rxg6? fxg6 (Kxg6? 45.Qf6+ Kh7 46.Rf5! +) 45.Rf8 Rg7! +<>> and we're done. Had not looked at <44.R4f5!!> at all. Interesting. Usually when teaching combinations (do this to children and adults alike) the most useful question is "what's the threat?". It's not as clear here. In fact, lets say Black plays his only waiting move <44....Bb7>. <45.Rxh5+!> we fire anyway. <45....gxh5> alternatives are mate. <46.Qc1!!> and Black's helpless to invading forces, except for throwing more material than White invested. 

Oct1218   TheaN: To actually make clear how this works after <44.R4f5 Bb7 45.Rxh5+! gxh5 46.Qc1!!> is seen by any interposing on the 6th rank. Mind that White threatens 47.Qh6+ Kg8 47.Rg6+ Kf8 48.Qh8# if Black does not. A) 46....Re6 seems to be a logical investment 47.Qh6+ Kg8 48.Bxe6! and mate to follow. B) 46....Rd6 47.Qh6+ Kg8 48.Rxd6 did not protect Black at all. C) SF9 goes with 46....Qc6 47.Qh6+ Kg8 48.Rxc6 + and an easy win for White. 

Oct1218   Walter Glattke: I found two parries after 44.R4f5 Qd8:
A) 45.Rxh5+ gxh5 46.Qd2 Qf8 B) 45.Rxf7+ Rxf7 46.Rxf7+ Rxf7 48.Bxf7 Qxd3  if that works!? I don't know. 

Oct1218
  cormier: click for larger viewAnalysis by Houdini 4: d 25 dpa
1. = (0.18): 13.a4 Qb6 14.axb5 cxb5 15.Ncd1 e5 16.d5 Rfc8 17.Bd3 a5 18.Ne3 a4 19.Rfd1 Qc5 20.Be2 Qb6 21.c3 Qc5 22.Rdc1 Qb6 23.Re1 h5 24.Qd3 b4 25.Nc4 Qc5 26.cxb4 Qxb4 2. = (0.12): 13.a3 Qb6 14.a4 e5 15.Rfd1 Rfe8 16.dxe5 dxe5 17.a5 Qa7 18.Na2 Rad8 19.Nc1 Nf8 20.Ncd3 Ne6 21.b4 Nf4 22.Qe1 Nxd3 23.Bxd3 Bc8 24.Qc3 Qc7 25.Rd2 Be6 26.Rad1 Rd4 27.Bf1 Rxd2 28.Qxd2 

Oct1218
  Jimfromprovidence: I have looked at the position for a good while. I'm seeing/hoping the main threat behind 44 R4f5 is to open the c1h6 diagonal for 45 Qc1/Qd2, seeing 46 Rxh5+ next. Anyway, there is a beautiful mate to work out if black tries 44...Kh6. click for larger view 

Oct1218   saturn2: I saw 44 R4f5 and subsequent Qd2 has some good potential. Other attacking schemes did not work for me. 

Oct1218   schachfuchs: Great, almost insane, puzzle from a not so known gem! Thanks & Greetings to the new CG puzzle team! 

Oct1218   Walter Glattke: Sorry, Jim, 44.Kh6 45.Qd2+ Kg7 46.Rxh5 Kxf6 47.Qg5+ Kg7 48.Qh6+ Kf6 49.Qh8# or
45.Kh7 46.Rxh5+ gxh5 (or Kg7 Qh6+ Kxf6 Qh8#) 47.Qh6+ Kg8 48.Rg6# Pf7 pinned. 

Oct1218   Andrew Chapman: Walter, 47. Qg5 is mate, no, in your first line? 

Oct1218
  Jimfromprovidence: Just realized now that <gofer> had first analyzed the position after 44...Kh6. <44 ... Kh6? 45 Rxh5+ Kxh5 (Kg7 Rxf7++ mating next) 46 Rf5+ gxf5 47 Qf6! mating after 5? spite checks> 

Oct1218   devere: <Carlos0012358: Black is behind the eight ball anyhow, but 44........gxf5 is an absolutely inexcusable move.> It is quite excusable, because after 44.R(4)f5!! there is no playable move for Black. 

Oct1218
  cormier: click for larger viewAnalysis by Houdini 4 Pro w32: d 27 dpa
1. + / = (0.45): 11.Nd3 00 12.a4 b4 13.Nb1 e5 14.dxe5 Nxe5 15.Qxb4 Qxb4 16.Nxb4 c5 17.Nd3 Nxd3 18.Bxd3 d5 19.Nd2 Rfe8 20.c3 dxe4 21.fxe4 Nxe4 22.Nxe4 Bxe4 23.Bc4 Bf5 24.Rae1 Bf8 25.Bf4 Red8 26.Be5 Ra7 27.a5 Bg7 28.Bf4 Bf6 29.Be3 Be7 2. + / = (0.38): 11.a4 b4 12.Na2 c5 13.dxc5 dxc5 14.c3 bxc3 15.Nxc3 00 16.Rfd1 Rfd8 17.Rac1 Ne5 18.Qc2 h5 19.Qb3 Qb4 20.Qxb4 cxb4 21.Na2 Rxd1+ 22.Rxd1 a5 23.Nc1 Bc6 24.b3 Kh7 25.Nh3 Bh6 26.Ng5+ Kg7 27.Nd3 Nxd3 28.Rxd3 Rc8 29.Rd1 Be8 30.e5 Nd7 31.e6 Nf6 32.exf7 Bxf7 

Oct1218
  condor: corkscrew immortal 

Oct1318   Howard: If one missed this puzzle when it was POTD, is there any way by which one can find out what the "crucial" position was after the fact ? 

Oct1318
  Sally Simpson: Hi Howard,
There is a POTD archive.
Tactics Archive 

Oct1318   Howard: It's only available, however, to premium members. 

Oct1318
  Sally Simpson: ***
Sorry, I never realised that.
Possibly look back on the thread for what previous posters are saying. You should get a good idea what the critical position was. It was here. (White to play)
click for larger view*** 


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