***Chess - Instructive Positions Thread ***

[YouKnowWho]

yeah, come to think of it it is probably close to losing for black. 1.. gxf6 2. Bh4 Bh5 3. Ng3 Bg6 4. f4 immediatelly and what do you do? h5 is met by f5. h6 can probably be met with some sort of defense of f5 square, then f5 followed by Nh5 and black is completely bind. Like no pieces can move pretty much..

[KyleJRM82]

Came across this on another (inferior) forum:

White to move:



Draw, because the knight can never get to g6 with the black king on f7. The fact that the knight can only get there on odd-numbered moves is an important facet of the piece.

[Mt.FishNoob]

just get knight to e6...? e: no won't work, I'm dumb.... pretty cool though

[Allen C]

Originally Posted by KyleJRM82

Came across this on another (inferior) forum:

White to move:



Draw, because the knight can never get to g6 with the black king on f7. The fact that the knight can only get there on odd-numbered moves is an important facet of the piece.

White would also win if he could play his knight to d8,d6,e5,g5, or h6 with the Black King on f8. So with Black playing Kf8-f7-f8 and White having to change colors each move with his knight, an easy way to see it is that White has to play to the same color square as Black's king which obviously can't happen. Therefor, without calculating at all, the knight starting on b1 or Black to move would be an automatic win.

[RoundTower]

This position came up in Gashimov-Ponomariov in the World Cup. The position about 10 moves earlier with N+P against bishop is well known and very instructive, analysis here:
http://www.chessbase.com/newsdetail.asp?newsid=7525

[valenzuela]

Here I played Rxb6, I still think its the best move I could have made.
The idea is to return the material advantage I have because my position is too clustered.
what do you guys think? I ended up winning the game as well

[HorridSludgyBits]

*grunch* from OP:

Spoiler:

The best I can find is 1...Qh2+ 2. Kf2 Rg6 and white has no way to defend the pawn (Rg1 and Qf3 are both met with Rf6 winning material). So 3. Qf3 seems his only move, which threatens dual mates on a8 and f7-8. 3...Rxg2+ 4. Ke1 and I can't see any way to continue the attack and defend the K - 4...f6 5. Qd5+ can't be good, and allowing him to take on f7 seems bad; there's no way to get out of the perp check without allowing a Q trade. A Q trade after black loses his f pawn is very unclear since the white passers will be formidable in either a R+P or a K+P ending, probably at least equal to the black g+h pawns.

So, I settled on forcing a Q trade under more favorable circumstances: 4...Qg3+ 5. Qxg3 Rxg3 and Black's k side pawns look to be plenty to win.

[HorridSludgyBits]

Ugh, didn't place spoiler tags, and didn't specify that this is from OP. And it's >30 mins since post. Sorry for the megafail. Maybe BJJ could clean up my mess?

[Noir_Desir]

valenzuela: I agree that the exchange sac is probably best and i would do it instantly in a blitz game. Still it's not the greatest structure to be an exchange down in and i wouldn't black expect to obtain winning chances against decent play from there. I'd say the positon is around equal.

[RoundTower]

it's around equal, but Black has no winning chances if he plays the right move?

I agree with the rest of what you say, but I think White is a little better after either Rxb6 or Qb7/c8, and very clearly better if he is allowed to go Rxa6.

[HorridSludgyBits]

Here's an endgame from a tournament game I played in 1995. Due to grad school, I'd been out of tournament chess for 8 years, and it showed. But I was able to swindle wins out of 2 lower rated opponents, including this one. Just the move before, Black resigned. So, if instead of resigning, Black plays the fairly forced B(e2)-a5, what is white's best line?

[Noir_Desir]

Spoiler:

i don't see an immediate forced win, so i would play 1. g3. Black doesn't seem to have any useful moves so we can create a winning outside passed pawn on the h-file before forcing the pawn endgame with d8=Q.

[HorridSludgyBits]

Spoiler:

Here's my analysis from that year: "...after 1...Ba5 2. d8=Q+? Bxd8 3. Rxd8 Ke7! Black wins back the piece with a drawn endgame." I think. I'm looking at 4. Rb8 Rxf8 5. Rxb7+ as having some practical winning chances perhaps, but it's hard to believe that Black with his more active king can't keep the scattered white pawns at bay.

Instead, I later found 2. g3!!, and Black is in virtual zugswang. The K can't move away from e7 or it can't administer the fork after d8, the R can't take the pressure off the N or the fork is no good. The B is stuck on the d8-a5 diagonal. The importance of g3 is that, otherwise, Black can play f4 and there will be no passed h pawn.

So, here's a sample line: 2. g3!! f4 3. gxf4 gxf4 4. Kg2 f3+ 5. Kf1 (Kxf3? Kg7) Bb6 6. c5! Ba5 7. h4 Bc7 8. h5 Ba5 9. h6 Bc7 10. h7 etc.

None of this was computer verified, so I'm open to corrections.

[Noir_Desir]

Spoiler:

in fact black is so tied up that we can probably march the h-pawn right down the board without having to enter the pawn endgame at all.

[KyleJRM82]

Here's one that came up today that I thought was interesting. I'm kind of cheating because I've examined it quite a bit on my own now, but I'm still not entirely sure I know what to do with it.



White to move, 15th move in a French Defense game.


A little spoiler space before I get into my thoughts on the position, which I don't want to have the entire post be in spoiler text.

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Okay, white essentially has two options. The first is to continue with his kingside expansion thematic to his triple-castle and try to pawn storm up the board.

15. f5 is the best option to do that, but it takes some calculation and vision to see that. 15. f5 exf5 16. Nxd4 will leave white with some nice tactical opportunities that should lead to a winning edge (computer considers the best line to be 16. Nxd4 Qh6+ 17. Kb1 b6 18. b4 Na4 19. Ne7+ Kh8 20. Qxd7 Nc3+ and white will get two minors for his rook, plus have a better overall position).

After 15. f5 Rac8 16. f6, white will get the mating attack chances he wants, but there's still counterplay for black:



The other option is 15. b4, which forces the line 15. b4 Na4 16. Nxa4 Qxd4 17. Rxd4 Bxa4, which leads to this position:



I'd be interested in thoughts on this endgame. The computer thinks white stands better here. He's got a king with better access to the center, and his bishop is completely free while black's is hampered by his pawns. But I just don't know, because black's rooks seem to be able to get active more quickly.