Deep Rybka 4 Insists I'm Ahead... I just don't see it.

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Pyke

A couple hours ago, I agreed to a draw in my final over the board game. I'll post the full game below for your viewing pleasure (though without analysis yet, since Deep Rybka is still going through it).

However, on the move where I proposed a draw, the position is as shown. White to move. Deep Rybka 4 insists that Black is better (-4.50). I've played around with the analysis board and just don't see it.

 

 

 

The whole game, if you're curious:

 

Time was more of an issue when the draw was agreed to for my opponent than me. With no increment, opponent had 31 minutes on the clock remaining, I had 89 minutes.

Pyke

Yeah, I saw that there was that mating threat too - but I'm not convinced that you ever have to get to that point.

Deep Rybka 4 seems convinced that after Kg2, Ne5, Nxg4, Black is better. I mean in principle it makes sense. I was really worried about two things though:

(1): If White had 6 tempo, she could promote a pawn on the Queens side of the Board. 

(2): Simultaneously, if I moved the King, White could promote through a pawn push on g5. The other big problem was White could keep moving his Bishop.

I've tried a Deep Position Analysis in Rybka - and it's convinced White has to hand over the pawn on g4 (if the Bishop takes back, the order of White having to move forces White to play a3 (because the king is already on g2). 

Maybe a stronger player than me would have won here.

Pyke

Yeah, I saw that line (as did Deep Rybka 4). The problem is once the pawn is on a white square, the Bishop can sacrifice itself to take it.

It thinks Nxg4 is winning - so I'm assuming the K + P end game that would result it prefers Black. Interestingly, playing Deep Rybka in that position it resigns. Maybe I just need more practice in K + P end game.

diomed1

  If white plays Kg2 doesn't Ne1+ win? Maybe I'm missing something but It looks like Ne1+, white's move, and g2 wins.

diomed1

 You have to play Kf3 if white moves Kf1 first before the g2 check. Really fun position, thanks for sharing this.

Pyke

No problem. Happy to share - especially since i'm genuinely confused on how to make this a win :p.

Ne1+ white plays Kg1, not Kf1. But even if Kf1, if you play Kf3, white now plays g5 and you can't stop the promotion. 

Utis44

Just curious. After white King goes somewhere, isn't Ne5 a winner?

Pyke
piotrk wrote:

Just curious. After white King goes somewhere, isn't Ne5 a winner?

Rybka says Ne5 followed by Nxg4 is winning. Rybka seems pretty sure of this proposition, that giving up the g3 pawn for the pawns on g5 and h4 plus the bishop (if the opponent takes back) is just outright winning.

I wasn't as convinced - I tried this is on the analysis board on here while it did analysis, and I'm not sure I could win that K&P end game. The other problem is with 6 tempo white can promote d5 - so I'm not sure how you address that. Rybka says White's best move is actually to let Nxg4 happen and not trade the Bishop off.

diomed1

  Kg1 loses to Nd3, Kf1 and there isn't time to promote.

diomed1
atarw

No way, I was in the same tourney!

diomed1


OK, I'm doing this from the analysis board as I don't have a computer program to check my lines but here goes ...

GothicChessed

Shredder 10 with its powerfull 3,4,5 Shredderbases was able to prove, after a little backtracking analysis, a win for black after 42...Ne5 and then Nxg4.

 

Here is the analysis:
Note that in every line that ends in the analysis, Shredder was showing mate scores. After letting to store each ending position and the scores of it and going backwards, it was able after some time to show a mate score after 42...Ne5 also.)



benonidoni

White is +3.31 Source"Fritz 13"

Pyke
benonidoni wrote:

White is +3.31 Source"Fritz 13"

That's the direct opposite of what the previous analysis showed.

benonidoni

My mistake Fritz has black ahead by 1/2 pawn but with correct knight moves is clearly ahead by 1'1/2 pawns. More actually with Kg2 and Kne1

Berder
Pyke wrote:
piotrk wrote:

Just curious. After white King goes somewhere, isn't Ne5 a winner?

Rybka says Ne5 followed by Nxg4 is winning. Rybka seems pretty sure of this proposition, that giving up the g3 pawn for the pawns on g5 and h4 plus the bishop (if the opponent takes back) is just outright winning.

I wasn't as convinced - I tried this is on the analysis board on here while it did analysis, and I'm not sure I could win that K&P end game. The other problem is with 6 tempo white can promote d5 - so I'm not sure how you address that. Rybka says White's best move is actually to let Nxg4 happen and not trade the Bishop off.

Black has a simple plan after capturing g4.  In words:  he captures the h5 pawn as well.  Then black's h pawn threatens to queen.  So, black marches his king over to the other pawns, and white's king is forced to use a lot of moves to capture the h pawn instead of following.  Meanwhile black's king can mop up the other white pawns and win.



waffllemaster

Yeah, too much computer usage.  Missed a very simple win with Ne5 as shown in post above this one.