| Jan-26-15 | | zydeco: Tough defense by Matanovic all the way through. It's hard to believe that 26....g5 is the best move, but I guess black needs to solve his back rank crisis without allowing 26....g6 27.Bh6+. |
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Dec-05-20
 | | Messiah: In all honesty, this puzzle of the day was way too difficult for me, especially right after waking up. Hopefully either someone will post valuable insights why Smyslov's way was the only precise winning, or I'll finish today's tasks earlier than expected, and then some real deep dive could enlighten me. |
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| Dec-05-20 | | Brenin: After a few minutes eyeing the concealed pin of Black's N, the loose a-pawn, and the possibility of a back rank mate or skewer by Ra8+, I realised that this was not a tactical puzzle but a test of endgame technique. Clearly Rd1-d7, followed by advancing the K, is the way forward for White, but the zwischenzug 33 Ra1 makes life easier, forcing a6 which denies the N an escape square and makes the a-pawn vulnerable to the light-squared B. Note that after 34 Rd1, Rd8 loses to 35 Bb7+. |
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Dec-05-20
 | | agb2002: White has a bishop for a knight.
Black threatens Rd8.
White has Rd1, Rc5 and Ra1.
After 33.Rc5 f6 34.Ra5 Kb8 the white rook has lost some mobility without achieving anything. After 33.Rd1 Na6 (33... Rd8 34.Bb7+ wins) 34.b5 Nb8 (controls d7 and touches the bishop) 35.Ra1 a6 36.e5 (36.bxa6? Nxc6 37.a7 Kb7 - +) 36... Rd8 and Black seems to hold. However, Ne6 is not possible after 33.Ra1, so 33... a6 (33... Kb8 34.Rd1 and 35.Rd7) 34.Rd1 followed by 35.Rd7 and White has the better position. |
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Dec-05-20
| | Messiah: Oh... if this is not a traditional tactics puzzle, then I already made a step towards understanding the position. |
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| Dec-05-20 | | awfulhangover: After the solution Ra1 I am just as confused as when reading the crazylooneygoogliboobly posting of chrisowen :-) |
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| Dec-05-20 | | ndg2: I found Rd1 (Rd8 isn't possible due to Bb7+ and rook loss) and I also thought about Ra1, ..a6 to fix blacks pawn structure, but failed to combine these two ideas. After immediate Rd1 maybe Na6 holds. |
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| Dec-05-20 | | RandomVisitor: After 33.Ra1 black might try fighting a pawn down with 33...Rd8 followed by Rd2
click for larger viewStockfish_20112916_x64_modern:
Found 510 tablebases
NNUE evaluation using nn-62ef826d1a6d.nnue enabled <50/60 28:06 +0.26 33.Ra1 Rd8 34.Rxa7 Rd2> 35.Ra5 f6 36.e5 f5 37.Rc5 Rb2 38.Rc4 h5 39.h4 gxh4 40.Rxh4 Rc2 41.b5 Rc5 42.Rxh5 Nxb5 43.Bxb5 Rxb5 |
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Dec-05-20
 | | Peligroso Patzer: Very interesting endgame, but not much of a puzzle. The point of the first move (33. Ra1), I think, is to force Black’s a-pawn forward so that the knight cannot occupy the a6-square to attack the b4-pawn (which White does not want to advance). This is pretty subtle endgame strategy, not the stuff of tactics puzzles. Of course, there is significant training value in being given a position and the task of finding the best way to proceed (without knowing whether the best plan involves an immediate tactical shot or a move of a deeply strategic character. It is just that I have always thought of this feature on the CG homepage as a tactics puzzle, so the departure from the traditional genre resonates discordantly. |
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| Dec-05-20 | | RandomVisitor: A final look at the position after 32...Kc8. White cannot force anything, it seems
click for larger viewStockfish_20112916_x64_modern:
Found 510 tablebases
NNUE evaluation using nn-62ef826d1a6d.nnue enabled <59/69 2:40:00 +0.18 33.Ra1 Rd8 34.Rxa7 Rd2> 35.Ra5 f6 36.e5 f5 37.h4 gxh4 38.Ra3 Rb2 39.f4 Rxb4 40.Kh2 Rc4 41.Bf3 Rc2+ 42.Kh3 h6 43.Kxh4 Rh2+ 44.Kg3 Rd2 45.Bc6 Kd8 |
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| Dec-05-20 | | saturn2: I saw the manouvre to position the rook on d7. Then the white king can proceed. Black is rather bound as shows 39...Nb5? 40. Rb7 mate |
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| Dec-05-20 | | goodevans: Even after seeing the solution it took me a while to understand it. It's the combination of <strategic and tactical> ideas that makes it so difficult. The main strategic idea (that I failed to grasp) is to get white's R to the 7th rank where it ties down black's K and N to stopping the tactical threats associated with a possible Ra8+. The most obvious point of entry is d7 but, as several have noted, the immediate <33.Rd1> fails to the zwischenzug <33...Na6> where the attack on white's b-pawn buys the N time to get to b8. If white tries to prepare Rd1 with something like 33.b5 then black will play 33...Rd8 and the chance is gone. But white has a zwischenzug of his own, <33.Ra1>. Contrary to what several kibitzers have said <this does not force black to play 33...a6>. He has at least two other plausible moves at his disposal... PLAN B: Black could instead defend the pawn with <33...Kb8> but now <34.Rd1> cannot be parried by <34...Na6> because black's K is on the same file as white's pawn (35.Rd7 Nxb4? 36.Rb7+). PLAN C: Black's third reasonable option is to abandon the a-pawn and get his own R into action with <33...Rd8>. After all, white has some loose pawns of his own that black might go after. The trouble with this plan though is that after <34.Rxa7 Rd3 35.b5> (or 34.Rxa7 Rd2 35.b5) black's R is tied down to preventing the tactical threat of b6 so can't go on the rampage. I believe all three responses are of similar merit. All three give white a strategic advantage that he can slowly but surely turn into a win. |
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| Dec-05-20 | | RandomVisitor: <goodevans>A long run on your plan C still shows that white cannot translate his position into an advantage. Not saying that it cannot be done...
click for larger viewStockfish_20112916_x64_modern:
Found 510 tablebases
NNUE evaluation using nn-62ef826d1a6d.nnue enabled <73/82 10:21:25 +0.20 33.Ra1 Rd8 34.Rxa7 Rd2 35.b5 Rb2> 36.Rb7 h5 37.b6 Na6 38.Rxf7 Rxb6 39.Rf8+ Kc7 40.Be8 Rb8 41.Rg8 Kd6 42.Bf7 Rxg8 43.Bxg8 Nc5 44.Bf7 h4 45.Bh5 Nd3 46.Kf1 Nc5 47.Ke2 Ke5 48.Bg4 Kd6 49.Bh3 Ke5 50.Kf2 Nd3+ 51.Kf1 Nc5 52.Ke2 Kf6 |
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| Dec-05-20 | | goodevans: <RandomVisitor> Cleary I'm no match for these silicon geniuses but just occasionally a bit of human logic transcends their node by node analysis. If I were white and had managed to tie down all black's pieces to stopping my b-pawn why would I exchange said pawn for any of his? Surely my plan would be to keep that irksome pawn for as long as possible whilst mobilising my K on the other side of the board. |
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| Dec-05-20 | | Brenin: <goodevans>: Good point: my writing that 33 Ra1 "forced" Black to play 33 ... a6 was too strong, and "induced" or "encouraged" might have been more reasonable. However, Smyslov was playing a human being, not a machine, and I think he was justified if he judged that Matanovic would reject the plausible alternatives to a6: 33 ... Rd8 immediately loses a P and makes the passed b-pawn a threat, while 33 ... Kb8 takes the K away from the centre and the K-side, where the later decisive action is likely to occur. |
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| Dec-05-20 | | Patriot: I don't buy it. Not a good chess problem. |
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| Dec-05-20 | | RandomVisitor: <goodevans>The truly annoying feature of the chess programs is that 'they' present their analysis without any kind of defense or argument as to why the line is deemed 'best.' In theory at least, it spent 10.5 hours trying to find a winning line for white, could not, and for some unknown reason it 'thinks' this is best play for both sides. At best, it is an unconfirmed opinion. At worst, it is a meaningless string of moves on which it is basing a move choice. If I had time I would try to see if holding onto the pawn does more for white's position. |
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Kibitzing
