Jul2805
  beatgiant: An interesting race in the end.
I believe Black should have played 50...Ra7! slowing down White's counterattack. An example is 50...Ra7 51. Nxc5 a3 52. Nb3 a2 53. c5 Ra3 54. Na1 Rd3, and Black is winning. 

Jul2905   sibilare: Moving the pawn would have won...
50..........a3
51 Kxb7 a2


Jul2905
  beatgiant: <sibilare>
<Moving the pawn would have won...>That also looks like a close race after 50...a3 51. Kxb7 a2 52. Nxc5 a1=Q 53. Kxc7, but maybe Black can still win it. 50...a3 51. Kxb7 a2 52. Nxc5 a1=Q 53. Kxc7 Qf1 54. d6 Qxc4 55. Kc6 Qf1 56. d7 Qg2+ 57. Kd6 Qxh2+ 58. Ke7 Qc7 59. Ne6 Qb7 60. Kd6, and I'm still having trouble seeing Black's win. 

Jul2905   sibilare: I don't think it a win in 1015 moves, But in 3040 moves. If 50....a3 51 Kxb7 a2 was played. Black two pawns are toast on the c file.
White has a potential pass pawn on d file, that is protected by the knight and the king. Which would be hard for a black Queen to take out. The black king is tied up protecting the pawns on the king side from the white knight. 

Jul2905
  beatgiant: <sibilare>
<I don't think it a win in 1015 moves, But in 3040 moves>I did keep looking for the win beyond what I posted above, and I'm saying I had trouble finding something convincing. It looks like Black would have to trade his queen for White's dpawn, leaving two pawns versus knight, and White's pieces are often close enough to stop Black's pawns. Do you have any specific improvements? One point of my suggested 50...Ra7! is that Black would gain a tempo after 50...Ra7 51. Kb8 a3 52. Kxa7 a2 53. Nxc5 a1=Q+ queening with check, so the win becomes much clearer. 

Jul2905   sibilare: Problem with 50....Ra7 is the following... 51 Nc1 a3 52. Na2... blocking the pass pawn. Black still can win thou. We do both agree that 50...Rb1 deserves a "?" and Young Capablanca stole a 1/2 point in this game. I don't know what the time controls were for this game... Maybe Corzo was low on time? I am not a Grandmaster so here are the games analyzed by engines. The first line shows the engines played the same moves on the 2nd line shows a new branch. Games below was set to 20 mins for all starting from black to move at 50..... < Hiarcs played the following. > 50... a3 51. ♔xb7 a2 52. ♔xc7 a1=♕ 53. ♘xc5 ♔g8 54. ♔c6 54... Qa8+ 55. Kb5 Qe8+ 56. Kb6 Qe2 57. d6 Qxc4 58. Nb7 Qc8 59. Nc5 Kf7 60. d7 Qd8+ 61. Kc6 Ke7 62. Kd5 g4 63. Ke4 Qa8+ 64. Kd4 Qa1+ 65. Kc4 Qa2+ 66. Kc3 Qxh2 67. d8=B+ Kxd8 68. Ne6+ Ke7 69. Nc5 Qc7 70. Kd4 Qxc5+ 71. Kd3 Kd6 72. Kd2 g3 73. Ke2 g2 74. Ke1 g1=Q+ 75. Kd2 Qcd4+ 76. Ke2 Qdd1# < Fruit 2.1 played > 50... a3 51. ♔xb7 a2 52. ♔xc7 a1=♕ 53. ♘xc5 ♔g8 54. ♔c6 54...Qd4 55. Kb5 g4 56. Nd7 Qb2+ 57. Kc6 Qxh2 58. Nf6+ Kg7 59. Nxg4 Qf4 60. Nxh6 Qxc4+ 61. Kd6 Kxh6 62. Ke5 Kg6 63. d6 Qc5+ 64. Kf4 Qxd6+ 65. Ke4 Kf6 66. Ke3 Kf5 67. Kf2 Qd2+ 68. Kf3 Qe1 69. Kg2 Kg4 70. Kh2 Kf3 71. Kh3 Qh1#
01
< Crafty 19.18 played > 50...a3 51.♔xb7 a2 52.♔xc7 a1=♕ 53.♘xc5
53.... Qe5+ 54.Kc6 Qxh2 55.d6 g4 56.d7 Qh4 57.Ne6 g3 58.d8=Q+ Qxd8 59.Nxd8 g2 60.Ne6 g1=Q 61.Kd5 Qg2+ 62.Kd6 h5 63.c5 Qd2+ 64.Ke7 Qd5 65.Kf6 h4 66.Nf4 Qf3 67.Ke5 Qe3+ 68.Kf5 h3 69.Nxh3 Qxh3+ 70.Ke4 Qd7 71.Ke5 Kg7 72.Ke4 Kf6 73.Ke3 Qd5 74.Kf4 Qxc5 75.Ke4 Qc1 76.Kd5 Qa1 77.Kc4 Ke5 78.Kd3 Qd4+ 79.Kc2 Ke4 80.Kb3 Kd3 81.Ka2 Kc3 82.Kb1 Qb6+ 83.Ka2 Qb2# 

Jul3005
  beatgiant: <sibilare>
Thanks for all those lines!
I have been arguing that 50...Ra7 is an easier win than 50...a3. Obviously, computers don't need to consider the concept of "easier win" so they just play greedy chess. But here are some specific comments. <Problem with 50....Ra7 is the following... 51 Nc1 a3 52. Na2... blocking the pass pawn. Black still can win thou.> I didn't give the 51. Nc1 line because it is so easy for Black: 50...Ra7 51. Nc1 a3 52. Na2 g4 53. Kb8, after which there are many ways to win, such as 53...Ra4 54. Kxc7 Rxc4 55. d6 Rd4 54. d7 h5 etc. and Black's obviously many moves ahead in this race. Moreover, after the engine's 50...a3, White also can play 51. Nc1 which just transposes to lines similar to above (one example of a Black win is 50...a3 51. Nc1 Rb1 52. Na2 g4 53. Kxc7 h5 54. d6 h4 55. d7 Rd1, etc.) so the Nc1 possibility is not really a distinctive feature for comparing the two lines. I will go through the lines posted by the engines in separate posts. That might take me some time! 

Jul3005
  beatgiant: This ending is so complicated, I have to open up my own chess engine (gnuchess). I play White (very slowly!), let gnuchess play Black, and post the result here. So far, I've had time to work on the line given by <Hiracs> and <Fruit 2.1>:
50... a3 51. Kxb7 a2 52. Kxc7 a1=Q 53. Nxc5 Kg8
Here, I varied with <54. Nb7> instead of the passive 54. Kc6 given by the engines. The game continued 54...Qe5+ 55. d6 Qxh2 56. c5 Kf7 57. c6 g4 58. Kc8 g3 59. d7 g2 60. d8=Q g1=Q 61. Nd6+ Ke6 62. Qd7+ Kd5 63. Nc4+ Ke4 64. c7 Qhf2 65. Qe6+ Kd4 66. Kb8 Qb1+ 67. Qb6+ Qxb6 68. Nxb6, with a drawn position. (For the record, gnuchess kept trying with 68...Qg3 69. Kb7 Qg7 70. Kb8 Qe5 71. Kb7 Qe4+ 72. Kb8 Qf4 73. Kb7 Qf3+ 74. Kb8 Qc6 75. c8=Q Qxb6+ 76. Ka8, and now the position is a Nalimov tablebase draw.) Admittedly, gnuchess is not a very strong engine. But I think I've made my point that this isn't what most humans would call an "easy win". 

Jul3005   sibilare: Searched the net a bit and found an annotated game... It is in Polish... http://www.vistula.risp.pl/historia...
So I searched a bit more for a translator and the moves that we were talking about is below. Taken from the page above. http://www.poltran.com/pl.php4
< brown text is where the moves were suggested > black text is where the actual moves played.
With (from) win white < 50...a3 51.Kxb7 a2 52.Kxc7 a1=Q 53.Sxc5 Qd4  + > 51.Kxc7 Rd1 < 51...a3 52.d6 a2  + > 52.Nxc5 a3 53.d6 a2? < It was better 53...g4 54.Nb3 h5 there was with connection of vertical  + strong > 54.Nb3 g4 55.d7 55.c5 h5 56.c6 

Jul3005
  Calli: Hooper in "the Unknown Capablanca" gives the win as 53...g4! 54.d7 h5 It looks pretty clear now. He continues with a long variation 55.d8Q+ Rxd8 56.Kxd8 h4 57.Nb3 g3 58.hxg3 hxg3 59.c5 g2 60.c6 g1Q 61.c7 Qg8+ 62.Kd7 Qf7+ 63.Kd8 Qd5+ 64.Ke7 Qc6 65.Kd8 Qd6+ 66.Kc8 a2 67.Na1 Kg7 

Jul3005   sibilare: < Cali: > I think that was Corzo's last chance at winning the game. In my last post < 53. Sxc5 > suppose to read < 53. Nxc5 >. I guess in the Polish language, they use S's in place of N's. 

Jul3005
  ckr: <Sibilare>
Sxc5 Ja, das springer! 

Jul3005   sibilare: < ckr: > er, uh, er, mmmm, yes! blink... 

Jul3105
  beatgiant: <Calli, sibilare>
Thanks again for the lines. I agree that both 50...a3 and 50...Ra7 would have won. As for 53...g4, we also have to look at 53...g4 <54. Nb3> similar to the actual game. In that case, one possibility is 53...g4 54. Nb3 h5 55.c5 h4 56. c6 g3 57. hxg3 hxg3 58. Kd7!, activating the cpawn too, and I didn't find a win for Black against this plan. 

Jul3105
  Calli: <Beatgiant> I am coming in late on the analysis and don't have time to catch up. It seems to me that on 53...g4 54. Nb3 then Kg7 and bring the king over will stop the white pawns. 55.c5 Kf6 56.c6 a2 and 57.d7 Ke7 or 57.Kd7 Ke6 etc 

Jul3105
  beatgiant: <Calli>
After the suggested 53...g4 54. Nb3 Kg7, now White has gained a tempo and so he can return to the plan of <55. d7>. For instance, 53...g4 54. Nb3 Kg7 55. d7 h5 56. d8=Q Rxd8 57. Kxd8 h4 58. c5, etc. and both sides are queening, so it looks drawish. 

Aug2705   LeSwamp: A) 8.Bxe4? Preferably 8.a3 Bxd2! 9.Nxd2 Qg5 (or 9...Qh4 10.00=) 10.Qf3 Nc5 11.h4 Nxd3+ (11...Qh6 12.e4 fxe4 (12...Nxd3+ 13.cxd3! with a small advantage for White) 13.Bxe4! Nxe4 14.Nxe4 Bxe4 (on 14...Bc6 or 14...Nc5, White would get a small advantage by playing 15.h5) 15.Qxe4 d5 (or 15...c6 16.h5 slightly favors White) 16.Qf3 and White ha a good possition and possibly a small advantage ; 11...Qg6 12.h5 Qg5 (12...Qh6 13.e4 Nxd3+ 14.cxd3 with a small advantage for White ; 12...Qf6 13.Qh3 Nxd3+ 14.cxd3 White small advantage) 13.Qh3 Nxd3+ (13...Bxg2?? would transpose in the main variation) 14.cxd3 Rg8 (14...Bxg2?! 15.Rg1 Bxh3 (only move) 16.Rxg5 Rg8 17.f3 f4 (only move) 18.e4! White's advantage) 15.Nf3 with idea Rc1 and b4. Small advantage White) 12.cxd3 Bxf3! 13.hxg5 Bxg2 14.Rh2 Bd5! 15.e4 Bb7 16.d5 with not so clear a position ; 8.Qe2 with idea a2a3 ; 8.00 with a balanced position. B) 9...00?! 10.c3! Black had the opportunity of securing a clear advantage : 9...Bxd2+ 10.Qxd2 (or 10.Kxd2 00 clearly in Black's favor) d6! 11.Nc4! 00 clear advantage Black ; 9...Qh4 also seems to lead to Black's clear advantage. C) 12.f3! Clearly not 12.Nxe4 h5! and... Bxe, winning! D)14.Ke2. Better was 14.Kd1! with idea Kc2 would have avoided the problem that will arise later in the game. E)18...e5. Missing 18...Rxd5! 19.c4 Rh5! 20.Nh6! e5 21.Nf5 (only move) Bc8! 22.Nxe7! Bxh3 23.Nd5 Na6 Black's small advantage. F) 31.Rxf3?! Capablanca misses 31.Kxf3! bxc5 32.Kg3 Rh5 (32...g5 33.Rf4! Rxf4 (33...Rh5 34.Rf7! Rh4 (34...Kg8 35.Rxc7 Rxc7 36.Nxc7 Kf7 37.e4 White clear advantage) 35.Rxc7! Rxc7 36.Nxc7 Bd7 37.Re1 White clear advantage) 34.exf4 Bd7! 35.fxg5 Bxb5 36.cxb5 Rg8 37.h4! hxg5 38.Re1 White advantage) Rh5 33.Rf7 (or 33.e4 White small advantage) Re8! 34.Re1 Ree5 45.e4 White small advantage. G) 33.Kxf3?! Better was 33.Bxd6! cxd6 (only move) 34.Kxf3 Rf8+ (34...Rh3+ 35.Ke4 Re8+ 36.Kd4 Rexe3 (36...Rd8 37.Rh1=) 37.Nxd6 Rd3+ 38.Ke5 Rhe3+! 39.Kf4 Black small advantage) 35.Kg3 Re4 36.Re1 Rf6 Black small advantage. H) 38...Ree8? 38...Ref7! 39.Re2 (39.Re3 Rf1! 40.h4 gxh4+ 41.Kxh4 Rh1+ 42.Kg3 (42.Rh3 Re1! 43.Kg3 Kg7 Black winning) Rg8+! 43.Kf2 Rh2+! 44.Kf3 Rh3+ 45.Kf2 Rxe3! 46.Kxe3 h5! Black winning) Rf3+ 40.Kg2 (40.Kg4? R8f4+ 41.Kh5 Kg7 and Rh4#) h5! 41.h4! gxh4! 42.Nxa5 (or 42.e5 h3+ 43.Kh2 Rf2+ 44.Rxf2 Rxf2+ 45.Kxh3 dxe5 46.Nxe5 Rxa2 Black winning) h3+ 43.Kh2 Rf2+! 44.Rxf2 Rxf2+ 45.Kxh3 Rxa2 46.Nc6 Rb2 Black winning I) 40.Rxe5?. Capablanca had to play 40.Nxa5 Ra8! 41.Nb7! Rxa2 42.Nxc5! Rff2 43.h3 Black advantage. J) 43.a4?! Three better alternatves which are better : 43.Nxc5 Rxa2 44.h4 Kg7 45.Kg4 gxh4 (or 45...Kg6 46.hxg5 hxg5 47.Na4 Black winning) 46.Kxh4 Black winning ; 43.h4 gxh4! 44.Kxh4 a4 45.bxa4 Re4+ 46.Kh5 Rxc4! 47.Kxh6 Rh4+! 48.Kg5 Rd4! 49.Kf6 c4! Black winning ; 43.h3 Rxa2 44.Nxc5 Kg7 Black winning. K) 50...Rb1?? The position which attracted the most comments. Personnally and with Fritz 8 as a helper, it appears that there are 2 ways that would have easily won the game for Corzo : the one that is the most popular amongst the gentlemen who poster variations above 50...a3 51.Kxb7 a2 (only move) 52.Kxc7 (52.Nxc5 a1Q 53.Ne6(53.Kxc7 transposes) Qa2 54.Nxc7 Qxc4 winning) a1Q 53.Nxc5 Kg8! wins for Black ; another way, which hasn't been discussed in here, seems to be 50...Rb2! 51.Kxc7 (51.Nxb2 a3 52.Na4 a2 53.Kxc7 a1Q 54.Nxc5 which transposes) Rxh2 52.d6 Rd2 53.Nxc5 g4 winning. L) 51...Rd1. Stronger was : 51...a3! 52.d6 a2 53.d7 a1Q 54.d8Q+ Kh7 55.Kc6! Rd1! and Corzo could still have played for the win, even if it is not that easily obtained. Here, would the white queen give check on the 7th rank, the black queen would interpose on g7. Corzo missed the chance to increase his lead to 30. Since Capablanca won the match by 1 point only, that could have changed the end result. 

Aug1008
  whiteshark: Quote of the Day
" The first two games were won quickly by [Corzo], but something in the third, which was a draw, showed me that he had his weaknesses and gave me the necessary courage and confidence. From there on he did not win a game... The victory made me, morally at least, the champion of Cuba. I was then twelve years old. "  Capablanca 

Jul0714   senojes: Corzo having 2 wins to Capablanca's 0, in this first to 4 wins match, Capablanca resolved to from now on open with 1. d4 instead 1. e4 with the aim of obtaining games that were more suited to his positional style and less suited to Corzo's tactical style. Corzo responds with 1...f5, the Dutch, again trying to take advantage of the 13 yearold's lack of book knowledge and experience. Capablanca opens with a ColleZukertort type system against Corzo's Queen's Indian type setup. Capablanca gets into trouble in the opening by 8. Bxe4 [0.50] when better was 8. OO [0.14]. Capablanca then incurs a weak f3 pawn to obtain an open gfile by 12. f3 exf3 13. gxf3. By 18. d5 Capablanca, in an inspired but unsound conception, sacrifices his d5 pawn with a view to also sacrificing his epawn, so that his Bd2 can bear down on Corzo's g7. But Corzo defends well and still hangs on to a slight advantage By 28.Nb5 Capablanca posts his N on a strong post attacking the c7 base of Corzo's Qside pawns, which will tie one of Corzo's Rs down defending c7. Capablanca's N can be only dislodged by Corzo's KB. So in what is either a blunder (unlikely) or an intuitive positional sacrifice, Capablanca allows Corzo's B to pin one of Capablanca's Rs and win the exchange. Then by 30. Bxc5 Capablanca exchanged Black's strong N leaving him with the R & N v 2 Rs endgame that he had presumably aimed for. But according to Houdini that position after 33...bxc5 was a win for Black [1.91]. 51. ... Rd1 Corzo belatedly realised that, although his apawn will queen one move before Capablanca's dpawn, the latter will queen with check! (51... a3 52. d6 a2 53. d7 a1=Q 54. d8=Q+). Capablanca had played the endgame well, if not flawlessly, but Corzo's R, passed apawn and 2 to 1 Kside pawn majority, should have won against Capablanca's N, passed d5 pawn and c4 pawn, the latter blocked by Corzo's c5 pawn. But Corzo's weak endgame play saw him, instead of advancing his Kside majority, against which Capablanca would have no answer, waste two tempi advancing his passed apawn when Capablanca's N would stop it. 53. ... a2 After this it is a draw because now these moves by Black's apawn are wasted tempi because White's N can stop it queening. The winning moves for Corzo were 53... h5 or 53... g4 54. Nb3 g4 Too late Corzo discovers what would have been the winning method, advancing his Kside majority and queening his gor hpawn. Now Capablanca only just has the time to queen his d5 pawn, winning Corzo's R, then win Corzo's c5 pawn, and be about to queen his cpawn, one move after Corzo would have queened his gpawn, but with nothing decisive that Corzo could do. Capablanca's in the comment above, from his "My Chess Career," shows that the 13 yearold was surprised that Corzo couldn't see the endgame win, when he clearly could. Hooper & Brandreth in "The Unknown Capablanca" commented: "This game was a revelation to Capablanca. After being outmanoeuvred once again in the middlegame he discovers that Corzo appears to have little understanding of the endgame." 



