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| Feb-11-12 | | jackpawn: Are Saturday puzzles getting easier or am I getting better in my old age? Found this one easily, but originally wanted to start out playing 28. Ba5 followed by 29. Bxg6. That didn't quite work so I reversed the bishops sacs. Yes! Did this after a night of drinking (which I seldom do). Maybe I discovered Alekhine secret of having combinational vision! Okay, probably not . . . |
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| Feb-11-12 | | Patriot: Before attempting to calculate anything, I first looked for what black is threatening and didn't see anything. I didn't even look at material differences (white has the bishop pair). Then I looked for "elements" or "seeds" (i.e. "seeds of tactical destruction") and noticed that the queen and rook are on the same diagonal and that Ba5 may be possible (even though it looks unsafe), and that Bxg6 looks interesting. Then I began to calculate. 28.Bxg6 fxg6 29.Qxg6+ Qg7 30.Qxh5 (threatening 31.Rg3) Qxg2#--oops! So I thought, "If I could get the rook to g3 first, black doesn't have this luxury. But is there enough time?" First I decided to take out a potential defender or problem piece, the knight. Since 28.Rg3 Ne2 could be an issue, I decided 28.Bxd4 cxd4 29.Rg3 to threaten 30.Bxg6. This still looks pretty good to me (at least I'm not seeing a good defense and white is getting at least 3 pawns for a piece plus an attack). But I never considered taking advantage of the seed with the queen and rook on the same diagonal. That's all I got after a few minutes. |
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| Feb-11-12 | | polarx: Another instance of an "I should have got this" puzzle. Saw the Bxg6 sacrifice and the Ba5 deflection/sacrifice, knew that the rook had to join the attack (and there is no other square than g3). But stopped there. Did not check whether Black had still a defense or the quite Rg3 was the beginning of the end. One is tempted to say that this puzzle was not so difficult after all. Quiet moves, that is the problem. |
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Feb-11-12
 | | Jimfromprovidence: I tried the 28 Rg3 line as well and found that it was too slow as <Patriot> noted because of 28..Ne2.
click for larger view I also tried 28.Bxd4 cxd4 29.Rg3 but tht line seems murky after 29...Rd7. 
click for larger viewWhite has 30 Qxh5 but black has 30...Bc4 to set up 31...d3. Then I found the winning line that those that got it have explained nicely. |
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| Feb-11-12 | | whiteshark: Hutsch took a lot of punishment. |
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| Feb-11-12 | | VincentL: "Very Difficult"·
I am sure this involves 28. Bxg6 fxg6 29. Qxg6+ etc. but first I think we need to deflect
the black queen from the defence. So I like 28. Ba5 as the first move. Black must capture in order to avoid losing the exchange, so 28....Qxa5 and then 29. Bxg6. After 29......fxg6 30. Qxg6+.
If 30.....Kh8 31. Qf6+ Kg8 32. Rg3+ Kh7 33. Qg7#
If 30.....Kf8 31. Qh6+ Ke7 32. Qh7+ Ke8/Ke7 33. Rg3 and black cannot prevent 34. Rg8# If black declines the second bishop and plays something like 29....Qc7, white continues
30. Rg3 and I don´t think black can avoid mate.
This is what I have seen straight away after looking at the puzzle. Since it is marked
"very difficult" I am sure there must be more than this. But my time is up; let´s check. |
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| Feb-11-12 | | VincentL: I tried my line against Crafty, and the machine came up with 29.....Nf3+ !. After 30 gxf3 the rook´s path is blocked. The human sees most defensive resources. The computer sees all. |
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Feb-11-12
 | | Penguincw: 28.♗xf6 isn't too hard to find, but the follow up might be a little trickier. |
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Feb-11-12
 | | doubledrooks: The idea is to sacrifice both bishops-first the WSB with 29. Bxg6 and after 29...fxg6 sac the other bishop with 30. Ba5, deflecting the Black queen from defending its King. For example: 30...Qxa5 31. Qxg6+ Kf8 Rg3 and mate is unavoidable.
Best for Black might be 29. Bxg6 Nf3+ 30. Rxf3 Bxf3 31. Bxh5+ Kf8 32. Bxf3, giving White two minor pieces and two pawns for a rook. 
click for larger view |
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| Feb-11-12 | | Marmot PFL: Calculated to the final position quickly, but didn't find the mate after 31...Nf5. |
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Feb-11-12
 | | chrisowen: Here bxg6 us ill why it double in dig ba5!
Eminate in slowly it dawn in just alive re dead black against d5 a very homing TCP queenh6? Appeals after say I the in rook g3 white pugnacious aint so bxg6 fxg6 qxg6 doesnt that just loose to qg7 no me install ba5! In defence again pin aorta it queen in aim I the gab lade try as she might qg7 bxd8 and f7 re qu across in science d8 I teed in each again qxa5 littles feint rook slide a g3 nf5 or f3 eta flight knight off qg8 rate mate in three raise in juicy it bd5 hanging in the air bxg6 rakes in trellis it hope in garden tis tryst in aorta h6? O brave in e7 my liege coming to conclusion ba5 in but got reticence in rg3 first ill wind hasten d4 knight... see to my cooperation bxg6 re at win! As an aside why is right in delve a bxg6 together qxg6 low grace in wanders on g3 ard I gangs us good call it downer in g8 somewhat sarcastic! |
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| Feb-11-12 | | tacticalmonster: 28?
a) 28 Bxg6 fxg6 29 Qxg6+ Qg7- White is forced to trade with a lost ending b) 28 Bxd4 cxd4 29 Rg3 Rd7 30 Bxg6?! fxg6 31 Qxg6+ Rg7 32 Qe8+ Kh7 33 Qxh5+ Kg8 = c) 28 Rg3 Nf5 29 Bxf5 exf5 30 Qxf5 Rd7 =
d) 28 Ba5 Qxa5 29 Bxg6 fxg6 30 Qxg6+ Kf8 31 Rg3 Nf5 (31 Ke7 32 Qh7+ Ke8 33 Rg8#) 32 Qg8+ Ke7 33 Qh7+ Ke8 34 Rg8# |
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Feb-11-12
| | chrisowen: Good knightd4, nearly it is black in get it isnt quick enough queen. Rook in g3 one again stayed it herring - bg6 is the move king must allow ground for knight f5 in danger it doesnt work in grave queen stilling again green drop g6 after glide back lein on g8 queen ha mater it zap in three par course it testament in white ingenuity on finding ba5! One that I realise escaped me but ill think again engine work in g6 skid in basket inch up ba5! Reckon it down in among it queen stead yet it almost in afraid it toing suspect re ally it qxa5 in short it demise rich in picking glory it each in wagon a describe it allegory bishop in belly up here low and sundry it can anyone giving support for home leg in 28th castles even better in g6! In direct it's no sacrifice digs kudos SM and what a find in everest ables sit in fetching kingf8 in career it seem like one of Tommy's quids in it analogy <Bd5> us machine trax like lorry... black truck carrying tortoises collided with a a van full of terrapins... a turtle distater! |
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| Feb-11-12 | | agb2002: White has the bishop pair for a bishop and a knight. Black can play ... Nf3+ if necessary to create problems in the coordination of the white pieces. After 28.Bxg6 fxg6 29.Qxg6+ Qg7 the white queen cannot leave the g-file due to ... Qxg2#. This suggests 28.Rg3, with the double threat 29.Bxg6 and 29.Qxh5, however 28... Ne2 29.Bxg6 Nxg3 looks bad for White. Another option is 28.Bxd4 cxd4 and now 29.Rg3:
A) 29... Rd7 30.Qxh5
A.1) 30... Kf8 31.Qh8+ Ke7 32.Bxg6 fxg6 33.Rxg6 + -.
A.2) 30... Kg7 31.Bxg6 fxg6 32.Rxg6+ and mate soon.
A.3) 30... Bc4 31.Bxg6 fxg6 32.Rxg6+ Rg7 (else mate in two) 33.Rh6 A.3.a) 33... Rh7 34.Qe8+ Kg7 35.Rg6#.
A.3.b) 33... Rd(e,f) 34.Rh8+ Kg7 35.Qh7#.
A.3.c) 33... Kf8 34.Qf3+
A.3.c.i) 34... Rf7 35.Rh8+ Ke7 (35... Kg7 36.Qh5 + -) 36.Qxf7+ Kxf7 37.Rh7+ Ke8 38.Rxc7 Bb3 39.Rc6 d3 40.Rd6 + -. A.3.c.ii) 34... Qf7 35.Rf6 + -.
A.3.c.iii) 34... Ke7 35.Qf6+ Ke8 36.Rh8+ + -.
A.3.c.iv) 34... Ke8 35.Rh8+ Kd7 36.Qf6 + -.
A.3.c.v) 34... Kg8 35.Qa8+ Kf7 36.Rf6+ Ke7 37.Qf8+ Kd7 38.Qxg7+ + -. A.4) 30... Bc6 31.Bxg6 fxg6 32.Qxg6+ Rg7 33.Qxe6+ Kf8 34.Rxg7 Kxg7 (34... Qxg7 35.Qxc6) 35.Qg4+ and 36.Qxd4 + - [5P vs B]. A.5) 30... Bb7 31.Qg5 followed by h5.
B) 29... Bc4 30.Bxg6 fxg6 31.Qxg6+ Kf8 (31... Kh8 32.Qh6+ Qh7 33.Qf6+ Qg7 34.Qxg7#) 32.Qg8+ Ke7 33.Ke7 Rg7#. C) 29... Kf8 30.Bxg6 fxg6 31.Qf6+ Ke8 32.Rxg6 Qf7 33.Qg5 + -. |
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Feb-11-12
 | | OhioChessFan: <TacticalMonster: b) 28 Bxd4 cxd4 29 Rg3 Rd7 30 Bxg6?! fxg6 31 Qxg6+ Rg7 32 Qe8+ Kh7 33 Qxh5+ Kg8 = > 30. Qxh5 1-0
click for larger view |
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Feb-11-12
| | OhioChessFan: And <agb> has that one already. Well done, gents! |
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| Feb-11-12 | | agb2002: I saw both 28.Bxg6 and 29.Ba5 but thought that Black had 28... Nf3+. However, after 29.Rxf3 Bxf3 30.Bxh5+ Kf8 31.Bxf3 White has a winning position. |
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| Feb-11-12 | | gofer: I looked at Bxg6 immediately. Much later, when I knew it didn't work,
I saw Ba5! Finally, even later, I saw that Bxg6 does work after all as long as the deflection of Ba5 comes with it! <28 Bxg6 ...>
As black isn't attacking anything and is about to lose Ph5 too, black has
no choice but to except the sacrifice!
<28 ... fxg6>
<29 Ba5!! ...>
A brilliant deflection. If black accepts then mate is not far off. 29 ... Qxa5
30 Qxg6+ Kf8
31 Rg3 ...
Mate is inevitable as white has cut off the escape route
of e8-d7-c8 and none of black's pieces can get back to help. 31 ... Re8 32 Qf6#
31 ... Rd7/Qc7 32 Qg8+ Ke7 33 Rg7#
31 ... Nf5 32 Qg8+ Ke8 33 Qh7+ Ng7 33 Rxg7+ Ke8 34 Qh8# Black has no choice but to give up the rook! At which point
black is a pawn and an exchange down and so everything is going
to be very difficult from now on. I am not sure exactly what
black will play, but it could be...
<29 ... Qf7>
<30 Bxd8 Nf5>
<31 Rc3 c5>
<32 f3 ...>
White threatens g4 breaking through black's kingside and following that
up with Rh3. It looks pretty okay for white...
Time to check... |
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| Feb-11-12 | | TheoNov: Yes, 28.Bxg6 did seem too obvious, and the problem is that it just didn't seem to work with the Black Q is so nicely placed for defense. Of course, this is because I completely missed the key move 29.Ba5!! So then I started looking at the simple 28.Bxd4 cxd4 29.Rg3, as have mentioned. In this position, it seems that White has an extremely dangerous attack, and it is hard to see how Black can escape unscathed: 
click for larger viewThe most obvious response, 29...Kf8 fails to 30.Bg6 fxg6 31.Qf6+ Qf7 32.Qxd8+. Probably the only defense that prevents immediate disaster for Black is 29...Rd7, but this allows White to nab a pawn with 30.Qxh5, for starters, and Black's pain does not end there. We can see that the h-pawn push is coming, and the Black K remains in critical condition with the Q, R, B and h-P all hyperactively pounding on his shaky fortress. Black is bound to lose material to prevent mate. I verified this with Houdini, and it gives +1.96 (18/65) with 31...Bc6 as the (slightly) preferred continuation, but it could not find anything satisfactory. So it looks like 28.Bxd4 also wins, but not as convicingly as the real solution. |
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| Feb-11-12 | | waustad: The Ba5 kind of reminds me of the Spassky vs Fischer game 5 when a bishop sac forces the queen to go where she doesn't want to be. |
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| Feb-11-12 | | M.Hassan: <OhioChessFan: Had a bad morning. MHassan refernced it too.> Particularly that I worked hard on this puzzle. To be quite honest:
Ba5 did not occur to me at all and secondly I was thinking and still think that the Knight on d4 was in a very good position and the reason that I started with 28.Bxd4 was that I wanted to move the Rook to g3. If the Knight was kept on d4, he could jump to e2 forking Rook and the b1 Bishop
and these were the theories bringing bad morning!(as you say) to me.
Have a good rest of the weekend |
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Feb-11-12
 | | Phony Benoni: While thinking about why 28.Bxg6 worked and 28.Ba5 didn't, a thought occurred to me.
click for larger view28.Bxg6 and 28.Ba5 are both forcing moves in that Black's responses are limited to some extent. If Black refuses the bishop after 28.Bxg6 and finds a sufficient defense, he loses a pawn. No fun, but not a disaster. On the other hand, if Black refuses the 28.Ba5 sacrifice he loses a whole rook. No defenses. Catastrophe. So 28.Ba5 is the more forceful move in that it limits Black's responses to a greater extent. And it seems that when you have two forcing moves to make but the order is not predetermined, it may well be better to save the more forcing move for later. If the combination is not completely forcing, a player who has accpeted a sacrifice has additional defensive options such as counter-sacrificing. Therefore, that is when you want to play the sacrifice he can't refuse. Of course Random Tactical Factors take the "Always" out of chess. But this may be something to keep in mind when you need to make a couple of sacrifices and are trying to decide the order. |
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| Feb-12-12 | | Once: <Phony Benoni> That's an interesting point. Double piece sacrifices require a slightly different way of thinking about the balance between material and mate. First off, let's put to one side pseudo sacrifices - the sac-my-queen-unavoidable-mate sacrifices. They are a special case and we don't need to worry about them. With those out of the way, most sacs give the sackee a choice - accept or decline. So 28. Bxg6 allows black a choice of taking the bishop and running into white's main line or declining it and losing a couple of prawns. The sacker needs to calculate two eventualities - sackee accepts or sackee declines. Forced line or material. Both eventualities need to work for the sacker or the sac isn't worth playing. But the balance changes when we are looking at a line which involves multiple sacrifices. When we throw lots of wood onto the fire we need to be careful about the sackee sidestepping our forced mating line and making the material choice. "28. Bxg6 first" works because the cost to black of declining is a couple of prawns. But accepting the sac leads to a forced line with mate or bigger material losses further down the line. That sac works on its own. It is a self-contained deal, take it or leave it. But "28. Ba5 first" is a different kettle of fish because it gives black a chance to bail out of the forced lines into a less ruinous material exchange. Interesting line of thought. Thanks. |
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| Feb-17-12 | | Jafar219: <Jafar219: Wow! Double rook sacrifice.> Bishop :) |
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| May-12-15 | | whiteshark: btw <26... Rd7> fully equalizes. |
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