< Earlier Kibitzing · PAGE 3 OF 3 ·
|Jun-04-08|| ||johnlspouge: <<goodevans> wrote: If I'm to be truly honest then I would say there was a third element to solving the puzzle - seeing the danger that that the king could defend against the g-pawn if the pawns are pushed in the wrong order. But I would still contend that recognising this danger is enough and that you don't have to work each line through to the end to claim a "solution". If you did then I doubt if anyone could "solve" a Sunday puzzle!>|
In any problem domain, the definition of "solution" is exactly that, a definition. People can respectfully differ on their definition. In support of your definition, my previous posts have pointed out that recognition of "a winning position" depends on the observer's skill. I generally carry my analyses to a P advantage as the standard for a won position.
As an aside, you might be surprised at how many Sunday puzzles can be "solved" to that standard. (On Sunday, I do most of my computer-assisted analysis after I post.) The only consistent exceptions to complete solution are the monster two-piece sacrifices to make a K walk a tightrope on the third rank with a R cutting off the second rank. It just depends how determined you are and how much time you are willing to spend.
I find your response entirely reasonable, because you are not "fooling yourself": you acknowledge a hidden layer of danger that must be navigated before 61...Nxg3 is a winning move. Your intuition is much better than mine, however, if you also saw without explicit calculation that the danger can be navigated safely.
|Jun-04-08|| ||Jatayu: <mostlyaboveaverageJoe> 'easier' is a very relative concept, depending not only on experience and training but on the way that your brain works, the way you visualize. I found today's much easier than Tuesday's, but that's just me. But both are good puzzles.|
|Jun-04-08|| ||TheaN: 3/3
Actually, my claim is doubtful, as I didn't look further than the first two Black moves. However, OTB, I probably would've seen the required combo before saccing the Knight, and I certainly would have after Be5. Take note that the pawns are too far apart to make the Bishop stop one and the King the other, so the sac itself was obvious, and that it won was also obvious.
Neat, but Ne3 seems to win easily as well, even in a piece endgame.
What else, really? The two pawns pose the same threat, White only has the other option of defending a3.
--a--62.Bg8 Ne4+ with g3
Any other move allows White to win a tempo, either with the same check or by threatening the Bishop.
As obvious as it is. The square is free now.
Well, yeah, I actually kinda stopped at Ka3. That there is a win is obvious: the pawns are on white squares, so they cannot be threatened. However, if White's King gets too close to the g-pawn, he has the remaining option to sac the bishop into b2 with a draw. So Black should be consistent by using an overworked piece with:
and White is too late.
|Jun-04-08|| ||johnlspouge: <<dzechiel> wrote: <dzechiel wrote: [snip] and again one of the pawns will queen.> [snip] But this isn't correct! [snip] I can't believe <<<>>--he--> overlooked this!>|
I am afraid I have contributed to a grave psychological problem.
Are you talking to yourself, <dzechiel>? :)
|Jun-04-08|| ||goodevans: <Vollmer: I don't mean to split hairs but it seems that overloading the Bishop is the initial key ... the deflection with g3 comes later>|
I'm happy to split hairs with anyone! Just to prove it I'd say the bishop gets deflected twice.
|Jun-04-08|| ||YouRang: I agree that it's one of the easier Wednesday's in a while. Almost without using our brains we know that we want to get our king to a3 and then a2 to support our b-pawn, but it's blocked by the bishop.|
Can we distract the bishop? Sure we can: 61...Nxg3 creates another passed pawn, and the bishop ends up having to stop two pawns at once -- which it can't.
|Jun-04-08|| ||JG27Pyth: This is pretty standard stuff... timely endgame minor piece sac in order to queen a pawn. |
You've <got> to see that g3 is the only winning move after the sac to collect full credit IMO. The first move is very easy (*as someone has pointed out there aren't many possibilities to begin with) ... so accuracy in the line is _required_.
I <heart> endgames (and endgame puzzles).
|Jun-04-08|| ||johnlspouge: <<JG27Pyth> wrote: ... so accuracy in the line is _required_.> |
Almost everyone is going to get the first move today, so the puzzle provides a test of character more than anything else.
Here, we have just heard from a guy with a great sense of humor, perhaps a touch obsessive, with just a hint of occasional self-flagellation...
Always nice to hear from <you>, <JG27Pyth> ;>)
|Jun-04-08|| ||dzechiel: <johnlspouge: I am afraid I have contributed to a grave psychological problem.|
Are you talking to yourself, <dzechiel>? :)>
Well, kinda. After making my original post last night, I saw a number of people proclaim that after 61...Nxg3 that the play would go "62 Bxg3 Ka3 then ...Ka2 and the b-pawn could not be stopped."
I thought this was an over simplification in that the b-pawn can always be stopped (but at the expense of having the g-pawn promote). I set out to compose a message to this effect and demonstrate that the position wasn't as simple as some people thought.
I tried to use my original analysis to show that the b-pawn COULD always be stopped, and during that I noticed that the g-pawn could be stopped as well! This was when I realized that my original post was flawed.
Now I wanted to be the first one to show the correct analysis, so I decided to treat my original post in the third-person (I thought it would be a little amusing). Unfortunately, two other users had already posted the correct line, noting the necessity of 63...g3 for success.
|Jun-04-08|| ||kevin86: A great piece of chessboard magic with just seven pieces. After 62 ♔b2 ♘e2 imprisons the king on the a and b files and guards both g3 and g1. White must then give up bishop for pawn and the black knight will usher home the lone remaining pawn.|
Of course,62 ♗xg2 is met by ♔a2 and the pawn will queen.
|Jun-04-08|| ||kevin86: A slight correction: If 62 ♗xg3 ♔a3 63 ♗d6+ ♔a2 and the pawn cannot be stopped|
|Jun-04-08|| ||zenpharaohs: Once: "the only line worth investigating turns out to be the only line that wins!"|
We have already seen that
61 ... Nxg3
61 ... Ne3
win. (There are actually two variations to 61 ... Ne3, depending on which pawn promotes.)
The question is whether a third line
61 ... Nh2
also wins. After some analysis, it looks drawn but I can't prove that yet.
|Jun-04-08|| ||jovack: the pawns are too far, white cant handle both threats|
|Jun-04-08|| ||lopium: Wow, I got it. Nice finish.|
|Jun-04-08|| ||YouRang: <JG27Pyth><I <heart> endgames (and endgame puzzles).>|
Or, <I ♥ endgames...> :-)
Have you seen this endgame puzzle? (I've shown it before, but it's one of my favorites):
click for larger view
White to move and win.
|Jun-04-08|| ||tatarch: Hmm-- have not seen it before, but my guess is Bb1 and then get in the way of the black king?|
I'll admit that I never calculate out these endgame puzzles, just look for the basic idea and hope it works in the end.
|Jun-04-08|| ||johnlspouge: <<YouRang> wrote: <JG27Pyth><I <heart> endgames (and endgame puzzles).>
Or, <I ♥ endgames...> :-)>|
Hey, <youRang>! Nobody likes a ❢❣❤❤❥ing smart-❦❧❧!
|Jun-04-08|| ||gambitfan: pretty easy to find the solution... by elimination !|
you cannot move the King (doing so you lose the pawn)
you cannot move either of the two pawns...
the only piece to move is therefore the knight !...
|Jun-04-08|| ||dzechiel: <YouRang: Have you seen this endgame puzzle? (I've shown it before, but it's one of my favorites):>|
It looks to me like 1 Bb1 is the solution. If black charges the pawns, then the white king can prevent black from building a fortress. If black takes the bishop with then 2 Kb3 to trap the black king against the board. Walk the black king over to the g-file (if black pushes his own pawn, then the white king can capture it outright). When ever the black king moves away from the g-file, then white can push his own pawn and capture the black pawn with his king.
So it might go
1 Bb1 Kxb1 2 Kb3 Kc1 3 Kc3 Kd1 4 Kd3 Ke1 5 Ke3 Kf1 6 Kf3 Kg1 7 Kg3
now black must move "away" from the g-file or push the pawn.
7...Kf1 8 g6 Ke2 9 Kf4 10 Kd3 Ke5 11 Ke3 12 Ke6 Ke4 13 Kf7 Kf5 14 Kxg7 1-0
How close is this?
|Jun-04-08|| ||zb2cr: Hi <dzechiel>,
Thank you for your appreciation of my pointing out that the Pawn move ... g3 is necessary to finish matters off. Since many regard your careful analyses as setting the standard for this site, a word of appreciation from you is to be prized.
Your authorship of a chess column shows in your kibitzing here; today's example was a fine, transparently clear, verbal explanation of the themes within today's puzzle. Thank you!
|Jun-04-08|| ||YouRang: <dzechiel>, <tatarch> -- Yes, that's the idea. 1.Bb1, sacrificing the bishop is the only way to win, otherwise black's king wins the race to the northeast where he can either take the white pawn or defend the black pawn -- drawing in either case.|
And yes, after the 2 kings walk together, the key point is when the black king gets to f1, and then white plays g6! and can now get to the black pawn before black has a chance to defend it.
BTW, when I first posted it, <chessgames.com> gave the problem to a computer trying 1.Kb4?, and it managed to lose! :-)
|Jun-04-08|| ||spongeworthy: The first thing to notice about this position is that the white bishop is over-worked, guarding the pawn on g3 and the a3 square. Black wants to escort his passed b-pawn ...Ka3, Ka2 followed by b2, b1=Q. But the white bishop prevents this. |
However if 61. ...Nxg3. 62. Bxg3, (or else 62. ...Ne4+, clearing the way for the g pawn to promote.) ...Ka3. 63. Bd6+, ...Ka2, and the b pawn can queen.) Or 63. Be5, ...Ka2. and the b pawn still promotes. unless white wants to lose his bishop but then the g pawn will promote.
|Jun-04-08|| ||jheiner: Black to Play. Thursday. Medium/Easy.
Material: N vs. dark B engame. Black has 2 P's, one passed. Key feature is to look at the color of the B and promotion squares. The b-pawn promotes on light and g-pawn on dark. The b-pawn is on the 6th rank, and is very powerful.
Wish List: The d6 B prevents the Black K from going to a3-a2 where it would protect the b3 pawn promotion. Is there way to deflect the dark-squared B?
Idea: With 61...Nxg3, Black creates a second passed pawn far from the defending K. If White does nothing, Black has won, since the second pawn will march down, be traded for the B and then it will be K+N+P versus K. So White's response is forced.
61...Nxg3 62.Bxg3 Ka3 63.b2
The White K obstructs the B from defending b2. The Black K can go to a2 safely and the dark B cannot prevent promotion on b1.
Time to check. Got it, but late to the party today and looks like some great kibitzing.
|Jun-04-08|| ||234: Tuesday puzzle <40. ...?> Jun-03-08 J Perlis vs Vidmar, 1907|
|Mar-16-13|| ||FSR: <YouRang: ... BTW, when I first posted it, <chessgames.com> gave the problem to a computer trying 1.Kb4?, and it managed to lose! :-) The Kibitzer's Café>|
The antecedent of your second "it" is unclear. I took it to mean that "a computer" managed to lose. Actually is was chessgames.com that did so:
<chessgames.com: <YouRang> Nice puzzle. Here in the office we tried to "cook it" with 1.Kb4 and also 1.Bf5, but 1.Bb1! is the only way to win. Testing some ideas against the computer, we succeeded in actually losing a game: 1. Kb4? Kxc2 2. Kc4 Kd2 3. Kd4 Ke2 4. Ke4 Kf2 5. Kf4 Kg2 6. Kf5 Kh3 7. g6? (7.Kg6 Kg4 =) Kh4 8.Ke6 Kg5 9. Kf7 Kh6>
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