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| Jun-30-16 | | dfcx: Black is up a pawn but white has the positions.
20.e5 opens the fourth rank and allows Ng5+ if black takes with his f6 pawn. A. 20...fxe5? 21.Ng5+ Kh8 (Khh6 22.Qh4#) 22.Qh4+ Kg8 23.Qh7# B. 20...Bxe5 21.Rxe5 wins a pawn (21...fxe5 22.Ng5+ mates) C. 20...other moves? 21.exd6 wins |
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| Jun-30-16 | | YouRang: Not too hard. :-) 20.?
click for larger view
Thought process:
The open h-file is screaming for our (white) Q to be on h4 and conduct a mating attack with Q+N. We just have to: (1) Get the Pe4 out of the way
(2) Support the Q at h7
(3) Seal off king's escape to f7
Obviously, our N can fill objectives (2) and (3) if it can go to g5, which is currently guarded by Pf6. Thus for black, it's imperative to keep Pf6 guarding g5. However, objective (1) <20.e5> also serves to attack that pesky Pf6. To keep the Pf6, black can capture with the bishop <20...Bxe5>, but white then steals the bishop with the rook <21.Rxe5!>
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The rook is immune! White has gained a piece.
Surprisingly, black played <21...fxe5?>, surrendering that critical defense of g5. This gives white an opportunity to demonstrate why the rook was immune: <22.Ng5+>
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Note that the move order is important. If 22.Qh4+, then 22...Kg8 and black still has time to move the rook to escape at f8. But with 22.Ng5, the Qc4 still seals off the g8 square and so the best black can do is <22...Kh8>.
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With all escapes blocked, it's a simple matter to mate: <23.Qh4+ Kg8 24.Qh7#> |
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| Jun-30-16 | | Patriot: <YouRang> Nice write-up! |
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| Jun-30-16 | | agb2002: White has the bishop pair for a bishop, a knight and a pawn. Black threatens 20... Qxb5.
If White had two free moves it would be possible to deliver mate with e5-Re4-Rh4#. This suggests 20.e5: A) 20... fxe5 21.Ng5+ Kh8 (21... Kh6 22.Qh4#) 22.Qh4+ Kg8 23.Qh7#. B) 20... Bxe5 21.Rxe5
B.1) 21... fxe5 22.Ng5+ and mate in two as in A.
B.2) 21... Qd1+ 22.Re1 Qd7 23.Qxc5 + - [2B vs N+P].
B.3) 21... Ned5 22.Ng5+ (22.Re1 Qxb5 looks more complicated) 22... fxg5 (22... Kh6 23..Qh4#; 22... Kh8 23.Qh4+ Kg8 24.Qh7#; 22... Kg8 23.Bxd5+ Nxd5 24.Rxd5 wins decisive material) 23.Bxd5 B.3.a) 23... Nxd5 24.Rxd5 Qxh3 25.Rxc5 + - [B vs 2P], some black pawns are weak and will be lost eventually. B.3.b) 23... Qxb5 24.Qxc3 with a similar conclusion as in B.3.a. B.3.c) 23... Nxb5 24.Bxg5 Nd4 25.Re4 Nf5 26.Rh4+ Nxh4 27.Qxh4#. C) 20... Nxb5 21.exd6 Nxd6 22.Qxc3 + - [2B vs N+2P]. |
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| Jun-30-16 | | AlicesKnight: it looks like 20.e5 wins a piece. If Black does nothing the bishop goes. If 20.... fxe5, 21.Ng5+ Now if ....Kh6, then Qh4# and if ... Kh8, Qh4+ and Qh7#. If 20.... Bxe5, then 21.Rxe5. If the Pawn captures the R the same lines follow as above. Let's have a look - seems to be what happened. <agb2000> is more exact than I am. |
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| Jun-30-16 | | stacase: What <Penguincw> said. |
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| Jun-30-16 | | gofer: Today's POTD took a while to analyse, but when I finally spotted the
mating threat it becomes very obvious that <20 e5> wins a piece. It
shouldn't win the game there and then, but it does win a piece. <20 e5 ...>
Taking the pawn with the f pawn is a bad idea.
20 ... fxe5
21 Ng5+ Kh8 (Kh6 Qh4#)
22 Qh4+ Kg8
23 Qh7#
Taking the pawn with the bishop is also a bad idea.
20 ... Bxe5
21 Rxe5 ...
Again taking the rook with the f pawn is a bad idea.
21 ... fxe5
22 Ng5+ Kh8 (Kh6 Qh4#)
23 Qh4+ Kg8
24 Qh7#
So black loses the bishop and it looks like much more
as Rxc4 looks rather nasty. Given that f5 is so strong
I wonder what black could hope to try...
<20 ... Qxb5>
<21 Qh4+ Kg8>
<22 exd6 Nf5>
<23 Qg4 ...>
Black is not dead, but its looking bleak. Though 23 ... Nxd6
looks on offer it is very very risky!
<24 Bf5 ...>
click for larger viewWhite has multiple threats, <Rb1 + Rxb7>, <Qxg6 + Bh6>, <Re7 + Rxg7+!>
all the while the black queen cannot move along the a4-e8 diagonal! So
<25 Rg1> is probably next whether black tries 24 ... Nce8 or 24 ... Nde8 ~~~
Yep. As its only a <Thursday> black chose one of the weakest defences! |
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| Jun-30-16 | | Cybe: White should play e5 already on 19th move. |
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| Jun-30-16 | | The Kings Domain: Good puzzle. Nice winning combination. |
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| Jun-30-16 | | Lambda: Got it eventually, but I was sidetracked at first by the mating pattern where the rook makes it to h4 via e4, and the queen remains on c4 to guard g8. |
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| Jun-30-16 | | eblunt: <Cybe:> White should play e5 already on 19th move. Not as strong as it was when played in the game. Doesn't win a piece IMO. Black can retreat the Bishop. Whites 19th move makes black either trap his own, or retreat his Knight to b8, blocking his Rook in. This makes the pawn push all the more potent when it comes. |
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| Jun-30-16 | | mel gibson: <Surprisingly, black played <21...fxe5?>, surrendering that critical defense of g5. This gives white an opportunity to demonstrate why the rook was immune> Yes - black can't take the Rook -
what a blunder. |
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| Jun-30-16 | | johnlspouge: < <Cybe> wrote: White should play e5 already on 19th move. > Stockfish rates 19.e5 as about 2.5 P; 19.b5 as about 2.3 P. The difference might be the status of the Q-side Ps. Both moves win Bd6, since the retreat on 19.e5 permits 19.e5 Bc7 20.exf6 gxf6 20.b6 Nb8 21.Qxc5
winning Ps to gain material, temporal, and spatial advantage. |
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Jun-30-16
 | | plang: It is possible that the difference between 2.5P and 2.3P is not statistically significant? I have asked on a number of occasions how accurate these evaluations are and have never received a satisfactory answer. |
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| Jun-30-16 | | saturn2: If the white knight would get to g5 and the queen to h4 black is done. All this is accomplished by the move e5 which I saw after some minutes. |
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Jun-30-16
 | | Jimfromprovidence: The best defense could be 21...b6.
click for larger view |
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| Jun-30-16 | | kevin86: I saw the first move, but wandered off after that. Nice finish- mate by queen and cavalier. |
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| Jun-30-16 | | Patriot: <Jimfromprovidence> You've got me curious on that one, because you always seem to find a tricky defense somewhere! So why doesn't the simple 22.Re1 refute this as a material plus? |
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| Jun-30-16 | | YouRang: <Patriot> Thanks :-) |
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| Jun-30-16 | | Pedro Fernandez: Greetings for my dear friends <Penguin> and <YouRang>. What about 20.Ng5+? Strange I don't see here some analysis about this move. What do you think my friends? After that, the move 21.e5 is a strong move. Of course there are a few possibilities but for sure you know what I mean. |
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Jun-30-16
 | | perfidious: A rock-crusher which admits of no antidote (or is it uncledote?). |
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| Jun-30-16 | | YouRang: Hi <Pedro>. If <20.Ng5+ fxg5 21.e5>
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It seems black has <21...Qf5> (threatens both ...Qxf2+ and ...Bxe5). |
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| Jun-30-16 | | johnlspouge: < <plang> wrote: It is possible that the difference between 2.5P and 2.3P is not statistically significant? > My guess is that the difference of 0.2 P is large enough to mean "something", but not much. Both evaluations usually mean an easy win (for a computer). As a practical matter, however, a human might prefer a position that a computer rates as inferior. For example, the final position I gave has the advantages I described (material, time, and space), but as mere flesh and blood, I find the advantages more nebulous than 2.5 P might indicate. |
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| Jun-30-16 | | Chess Dad: <<Plang>: <It is possible that the
difference between 2.5P and 2.3P is not statistically significant?> It depends on who's playing. Weak players like me make mistakes a whole lot bigger than missing the optimal move and instead choosing one 0.2P weaker than optimal. That mistake won't matter a bit.
But grandmasters? Make a handful of moves 0.2P worse then optimal, and suddenly you're down a real pawn, and not just a fractional accounting entry. |
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| Jun-30-16 | | Patriot: <Jimfromprovidence> I finally plugged your position into Stockfish and it likes 22.a4 best and 22.Re1 in close second. 22.a4 makes a lot of sense because 22...fxe5 is not even threatened! |
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Kibitzing
sac: 21.Rxe5