Move 23 discussion: Everyone vs stockfish

MooMoo2 · 2016-02-26, 04:25

The poll for move 22 just closed, and the most popular move was Nf5. Stockfish responded with 22...Nxb2, and the FEN is:
r5k1/1p3p1p/1p3p2/3p1N2/4rP2/8/PnP3PP/R2R2K1 w - - 0 23

Game so far: 1.e4 e6 2. d4 d5 3. Nd2 c5 4. Ngf3 Nf6 5. exd5 exd5 6. Bb5+ Bd7 7. Bxd7+ Nbxd7 8. O-O Be7 9. dxc5 Nxc5 10. Nb3 Nce4 11. Nfd4 O-O 12. Nf5 Re8 13. Nxe7+ Rxe7 14. f3 Nd6 15. Bg5 Nc4 16. Bxf6 gxf6 17. Qd4 Qb6 18. Qxb6 axb6 19. Rfd1 Re5 20. f4 Re2 21. Nd4 Re4 22. Nf5 Nxb2

richs · 2016-02-26, 05:26

23. Rxd5 per Mr. Barnes' previous analysis with which I still agree.

WMHalsdorf · 2016-02-26, 06:21

Quote:

Originally Posted by richs

23. Rxd5 per Mr. Barnes' previous analysis with which I still agree.

I agree.

gd_barnes · 2016-02-26, 09:20

Yep...23. Rxd5.

Brian-E · 2016-02-26, 09:33

I agree with 23.Rxd5 too.

The alternative 23.Rd4 (not the pointless 23.Rdb1? Nc4) intending to preserve the f4 pawn might be worth considering, but on general principles we should be exchanging pawns to achieve the draw.

After 23.Rxd5 I am wondering if Stockfish will shun the f pawn and reply 23...Re2 24.Nd4 Rd2 intending ...Re8. That might be better than the reply 23...Rxf4 analysed earlier.

However, I still think we should play 23.Rxd5 and see what it does.

gd_barnes · 2016-02-27, 05:08

Quote:

Originally Posted by Brian-E

After 23.Rxd5 I am wondering if Stockfish will shun the f pawn and reply 23...Re2 24.Nd4 Rd2 intending ...Re8. That might be better than the reply 23...Rxf4 analysed earlier.

However, I still think we should play 23.Rxd5 and see what it does.

I don't think it will shun the pawn because it would be weak for us to retract the night in response. Better would be:
23. ....Re2
24. Rd7 Rxc2
25. Rxb7

...and we are even on material and have an excellent position with the potential to be a pawn ahead. Black must waste a move by moving the h-pawn to free up the a8 rook (due to mate on the 8th rank if it is moved) and we are still threatening Rxb6 and Nh6+ potentially picking off the f7 pawn.

Brian-E · 2016-02-27, 09:29

Quote:

Originally Posted by gd_barnes

I don't think it will shun the pawn because it would be weak for us to retract the night in response. Better would be:
23. ....Re2
24. Rd7 Rxc2
25. Rxb7

...and we are even on material and have an excellent position with the potential to be a pawn ahead. Black must waste a move by moving the h-pawn to free up the a8 rook (due to mate on the 8th rank if it is moved) and we are still threatening Rxb6 and Nh6+ potentially picking off the f7 pawn.

More threatening than 24...Rxc2, I think, is 24...Rc8. Then as in the other line, if we play 25.Nd4 it replies 25...Rd2. Or 25.Rc1 Nd3. It seems to me that Black has serious threats if we don't play Nd4 on either move 24 or 25.

EDIT: That last line 25.Rc1 Nd3 is obviously incorrect. My mistake. I'll look further.

Brian-E · 2016-02-27, 09:55

Well, trying again, if we look at the line which you suggested: 23.Rxd5 Re2 24.Rd7 Rxc2 25.Rxb7 Black will reply 25...Nc4. While I agree that Black must use a move to play ...h5, I also think we have a job on our hands to prevent black's other rook coming to the second rank via d8 or e8. Our Nh6+ is nothing because it replies ...Kg7. So we have nothing attacking to do and must defend against the threatened invasion.

I can't demonstrate anything concrete further than that. I'm a weak analyst. But I don't share the confidence you express about our chances to draw.

gd_barnes · 2016-02-28, 07:24

Quote:

Originally Posted by Brian-E

More threatening than 24...Rxc2, I think, is 24...Rc8. Then as in the other line, if we play 25.Nd4 it replies 25...Rd2. Or 25.Rc1 Nd3. It seems to me that Black has serious threats if we don't play Nd4 on either move 24 or 25.

EDIT: That last line 25.Rc1 Nd3 is obviously incorrect. My mistake. I'll look further.

24...Rc8 ????? ...

25. Ne7+

forks the rook and black drops the exchange.

Just to be clear, you are suggesting that SF might play:
23. Rxd5 Re2
24. Rd7 Rc8??

Ya better look again. :-)

gd_barnes · 2016-02-28, 07:57

Quote:

Originally Posted by Brian-E

Well, trying again, if we look at the line which you suggested: 23.Rxd5 Re2 24.Rd7 Rxc2 25.Rxb7 Black will reply 25...Nc4. While I agree that Black must use a move to play ...h5, I also think we have a job on our hands to prevent black's other rook coming to the second rank via d8 or e8. Our Nh6+ is nothing because it replies ...Kg7. So we have nothing attacking to do and must defend against the threatened invasion.

I can't demonstrate anything concrete further than that. I'm a weak analyst. But I don't share the confidence you express about our chances to draw.

You have to look deeper. I agree that in that line black's best move is 25...Nc4 but it creates other problems for him. IMHO, the best line for us against: 23. Rxd5 Re2 is:

24. Rd7 Rxc2
25. Rxb7 Nc4
26. Rc7 (!)

Here, I believe black has 3 reasonable choices:
26...Ne3 forcing the exchange of rooks.
26...h5 (or some other quiet move) and play continues 27. Nd4 (!) Rc3 28. Ne2 Rc2 29. Nd4 and we can eventually force a 3-time repitition.
26...b5*

*We have a myriad of possibilities here including but not limited to 27. a4, g4, g3, Re1, and maybe even Rc5, etc. that all look good for us.

Regardless, in all of these positions we are even on material, our pieces are equally active, our pawn structure is much better, and we can more easily approach the center with our king in the end game; also an advantage. I do not see why you are so negative about our chances.

For the reasons above, I think that SF is much better taking the pawn with 23...Rxf4. He maintains the pawn advantage for as long as he can; something that programs are fond of when there are no intermediate-term winning chances.

Brian-E · 2016-02-28, 10:00

Yes, 26.Rc7 looks good for us in that line. But, as you say, Black is likely to play 23...Rxf4 as per your earlier analysis, in which case the situation will not arise.

Just to answer your question about why I am "negative" about our chances: I simply don't believe that we as a group are capable of avoiding defeat against this program, because top players like Nakamura fail to avoid defeat even though they will also be employing the anti-computer strategies that we have been using. I agree with you that our position seems safe and water-tight, but I don't trust us not to have overlooked something. I am assuming that none of us has succumbed to the temptation to cheat with software ourselves of course - that would be another matter.

My flawed efforts above were merely an attempt to show that we cannot have considered everything that SF might play. I didn't succeed in showing that, but my assessment of our chances remains the same.

Now... onward towards enlightenment, I suggest. Like everyone else so far, I advocate 23.Rxd5.

2016-02-26, 04:25	#1
MooMoo2 "Michael Kwok" Mar 2006 2²·5·59 Posts	Move 23 discussion: Everyone vs stockfish The poll for move 22 just closed, and the most popular move was Nf5. Stockfish responded with 22...Nxb2, and the FEN is: r5k1/1p3p1p/1p3p2/3p1N2/4rP2/8/PnP3PP/R2R2K1 w - - 0 23 Game so far: 1.e4 e6 2. d4 d5 3. Nd2 c5 4. Ngf3 Nf6 5. exd5 exd5 6. Bb5+ Bd7 7. Bxd7+ Nbxd7 8. O-O Be7 9. dxc5 Nxc5 10. Nb3 Nce4 11. Nfd4 O-O 12. Nf5 Re8 13. Nxe7+ Rxe7 14. f3 Nd6 15. Bg5 Nc4 16. Bxf6 gxf6 17. Qd4 Qb6 18. Qxb6 axb6 19. Rfd1 Re5 20. f4 Re2 21. Nd4 Re4 22. Nf5 Nxb2 Attached Thumbnails

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2016-02-26, 05:26	#2
richs "Rich" Aug 2002 Benicia, California 2×859 Posts	23. Rxd5 per Mr. Barnes' previous analysis with which I still agree.

2016-02-26, 09:20	#4
gd_barnes "Gary" May 2007 Overland Park, KS 5×2,459 Posts	Yep...23. Rxd5.

2016-02-26, 09:33	#5
Brian-E "Brian" Jul 2007 The Netherlands 6316₈ Posts	I agree with 23.Rxd5 too. The alternative 23.Rd4 (not the pointless 23.Rdb1? Nc4) intending to preserve the f4 pawn might be worth considering, but on general principles we should be exchanging pawns to achieve the draw. After 23.Rxd5 I am wondering if Stockfish will shun the f pawn and reply 23...Re2 24.Nd4 Rd2 intending ...Re8. That might be better than the reply 23...Rxf4 analysed earlier. However, I still think we should play 23.Rxd5 and see what it does.

2016-02-27, 09:55	#8
Brian-E "Brian" Jul 2007 The Netherlands 2·11·149 Posts	Well, trying again, if we look at the line which you suggested: 23.Rxd5 Re2 24.Rd7 Rxc2 25.Rxb7 Black will reply 25...Nc4. While I agree that Black must use a move to play ...h5, I also think we have a job on our hands to prevent black's other rook coming to the second rank via d8 or e8. Our Nh6+ is nothing because it replies ...Kg7. So we have nothing attacking to do and must defend against the threatened invasion. I can't demonstrate anything concrete further than that. I'm a weak analyst. But I don't share the confidence you express about our chances to draw.

2016-02-28, 10:00	#11
Brian-E "Brian" Jul 2007 The Netherlands 3278₁₀ Posts	Yes, 26.Rc7 looks good for us in that line. But, as you say, Black is likely to play 23...Rxf4 as per your earlier analysis, in which case the situation will not arise. Just to answer your question about why I am "negative" about our chances: I simply don't believe that we as a group are capable of avoiding defeat against this program, because top players like Nakamura fail to avoid defeat even though they will also be employing the anti-computer strategies that we have been using. I agree with you that our position seems safe and water-tight, but I don't trust us not to have overlooked something. I am assuming that none of us has succumbed to the temptation to cheat with software ourselves of course - that would be another matter. My flawed efforts above were merely an attempt to show that we cannot have considered everything that SF might play. I didn't succeed in showing that, but my assessment of our chances remains the same. Now... onward towards enlightenment, I suggest. Like everyone else so far, I advocate 23.Rxd5.