Difficult endgames

[Nordlandia]

Can black infiltrate/penetrate the white nerve center

[d]6k1/pp3p2/6p1/3p4/2pN4/P1P2P1P/1P1qR1P1/6K1 b - - 0 1



-----------------

Jens Enevoldsen vs Christian Poulsen, Denmark 1940

[d]5rk1/p1r2p1p/6p1/3B4/2p1N3/P5P1/4PP1P/R5K1 b - - 0 0

[Nordlandia]

[d]6k1/1p2bpp1/pr1p1n1p/4p3/P3P3/4R2P/5PP1/R4BK1 w - - 0 9

[d]2r3k1/1p2bpp1/p2p3p/4p3/P3R3/1Pn4P/2P2PP1/R4BK1 w - - 0 8

[yanquis1972]

latest SF seems to disagree w/ the posted analysis, at least at fairly shallow depths...shows g5 (instead of f5) as giving best winning chances.

curious what more time/better hardware/interaction by someone who knows what theyre doing yields.

[peter]

Hi Jon!

Can black infiltrate/penetrate the white nerve center

[d]6k1/pp3p2/6p1/3p4/2pN4/P1P2P1P/1P1qR1P1/6K1 b - - 0 1

I'd say, John is simply right with 2...g5 instead of ...f5.

http://www.talkchess.com/forum/viewtopi ... 72&t=63337

After 1...Qc1 2. Kf2 f5 and some Forward- Backward:

6k1/pp6/6p1/3p1p2/2pN4/P1P2P1P/1P2RKP1/2q5 w - - 0 1

Analysis by pedantFishW_2017-02-28_popcnt:

3.g4 fxg4 4.hxg4 Kf7 5.Kg3 b6 6.f4 a6 7.Nf3 b5 8.Nd4 Qf1 9.g5 Qc1 10.Kg4 Qg1+ 11.Kf3 Qh1+ 12.Kg3 Qf1 13.Rf2 Qe1 14.Kf3 Qc1 15.Re2 Qg1 16.Rf2 Ke7 17.Re2+ Kd7 18.Re5 Qd1+ 19.Kg3 Qd3+ 20.Kg4 Qb1 21.Re2 Qf1 22.Kg3 Kd8 23.Re6 Qg1+ 24.Kf3 Qh1+ 25.Kg3 Qb1 26.Re2 Qg1+ 27.Kf3 Qf1+ 28.Kg3 Kd7 29.Re5 Qa1 30.Rxd5+ Kc7 31.f5 gxf5 32.Nxf5 Qxb2 33.g6 Qxc3+ 34.Kf4 Qf6 35.g7 Qe6
-/+ (-0.79) Depth: 46/74 00:02:40 5201MN, tb=3982327

And after 2.g5:

6k1/pp3p2/8/3p2p1/2pN4/P1P2P1P/1P2RKP1/2q5 w - - 0 1

Analysis by pedantFishW_2017-02-28_popcnt:

3.Kg3 Kg7 4.Kf2 Kf6 5.Kg3 Qf1 6.h4 gxh4+ 7.Kxh4 b5 8.Kg3 a5 9.Rf2 Qh1 10.Nxb5 Kg5 11.f4+ Kh5 12.Nd4 Qh4+ 13.Kf3 Qg4+ 14.Ke3 Kh4 15.Kd2 Kg3 16.Ke1 Qh5 17.Ne2+ Kg4 18.Ng1 Qh4 19.Kf1 Qh7 20.Rd2 Kxf4 21.Kf2 Qh4+ 22.Kf1 Qd8 23.Nf3 Qb6 24.Ng1 a4 25.Nf3 Qe6 26.Ng1 Qd6 27.Rf2+ Kg4 28.Rd2 Qf4+ 29.Ke1 Qe5+ 30.Kf2 Qf6+ 31.Nf3 Qb6+ 32.Nd4 Kh4 33.Re2 Kg5 34.Rd2 Kg4 35.Kf1 Qg6 36.Kf2 Qd6 37.Kf1 Qf4+ 38.Ke1 Qh2 39.Nf3 Qd6 40.Nd4 Kg5 41.Kf2
-/+ (-1.23) Depth: 53/81 00:01:36 3045MN, tb=2666786

Besides of these outputs it seems even more logical too, if Black wants to prevent White's f4, to play ...g5 rather than ...f5, isn't it.

Here's SF's output after full Backward to starting position, I doubt this to be a sure full point anyhow:

6k1/pp3p2/6p1/3p4/2pN4/P1P2P1P/1P1qR1P1/6K1 b - - 0 1

Analysis by pedantFishW_2017-02-28_popcnt:

1...Qc1+ 2.Kf2 g5 3.Rc2 Qb1 4.Rd2 a6 5.Re2 Kh7 6.Rd2 Kg6 7.Rc2 Kf6 8.Re2 Qc1 9.Kg3 Qf1 10.h4 gxh4+ 11.Kxh4 b5 12.Kg3 a5 13.Rf2 Qh1 14.Nxb5 Kg5 15.f4+ Kh5 16.Nd4 Qh4+ 17.Kf3 Qg4+ 18.Ke3 Kh4 19.Kd2 Kg3 20.Ke1 Qh5 21.Ne2+ Kg4 22.Ng1 Qh1 23.Kf1 Qh6 24.Rd2 Qxf4+ 25.Ke1 Qe3+ 26.Ne2 Qe6 27.Kf1 Qf5+ 28.Ke1 Kh4 29.Nd4 Qe5+ 30.Kf2 Qg3+ 31.Kf1 Qf4+ 32.Ke1 Kg4 33.Ne2 Qf5 34.Rd4+ Kg5 35.Rd2 a4 36.Nd4 Qg6 37.Nf3+ Kf4 38.Kf2 Qb6+ 39.Nd4 Kg4 40.Ke1 Kg5 41.Kf2 Kh4 42.Kf1 Qc5 43.Ke1 Kg5 44.Kf2
-/+ (-1.23) Depth: 60/92 00:03:27 6544MN, tb=4133856

[Nordlandia]

It appears that it's a fortress or semi-fortress (pseudo).

Kasparov said that RN often need couple of pawns to equalize the queen. Equilibrium | Ceteris Paribus.

That knight on d4 is at least worth 1 pawns out of 2 in positional compensation for the material deficit.

Rules of knights
1. Knights need advanced support points to be effective.

C. A knight on the fourth rank is equal to a bishop and can withdraw for defense or venture even further for attack.

https://en.wikibooks.org/wiki/Chess_Str ... of_knights

[Nordlandia]

This one is rather interesting

Possible cook | Correction: Houdini 5.01 Pro found winning evaluation.

Draw

[d]3k4/2pq3p/pp5R/4P3/P6P/2PN4/1PN3K1/8 w - - 0 0



Analysis - http://www.viewchess.com/cbreader/2017/ ... 04562.html

[Vinvin]

This one is rather interesting

Possible cook | Correction: Houdini 5.01 Pro found winning evaluation.

Draw

[d]3k4/2pq3p/pp5R/4P3/P6P/2PN4/1PN3K1/8 w - - 0 0

https://cdn.pbrd.co/images/FKLi94bQc.png
Analysis - http://www.viewchess.com/cbreader/2017/ ... 04562.html

mainline :
[Event "?"]
[Site "?"]
[White "W"]
[Black "B"]
[Result "*"]
[FEN "3k4/2pq3p/pp5R/4P3/P6P/2PN4/1PN3K1/8 w - - 0 1"]

1. Nd4 Qg7+ 2. Kh3 Qxh6 3. Nf4 Ke8 4. Nde6 Ke7 5. Kg4 Kd7 6. h5 b5 7. a5 b4 8. Kf3 b3 9. c4 Ke7 10. Ke4 Kd7 11. Kd5
c6+ 12. Kc5 Ke7 13. Kxc6 *


After 1. Nd4 Qg7+ 2. Kh3 Qxh6 3. Nf4 clearly winning score with the 4 best moves :
FEN: 3k4/2p4p/pp5q/4P3/P2N1N1P/2P4K/1P6/8 b - - 1 3

McBrain_2017_v13_x64_modern:
...
34/92 01:36 1 567 664k 16 221k +28,59 3. ... Kc8 4.Nde6 Kb7 5.h5 a5 6.Kg4 c6 7.Kf3 b5 8.Ke4 bxa4 9.Kd4 Kb6 10.Kc4 a3 11.bxa3 a4 12.Kb4 c5+ 13.Kxa4 Kc6 14.Ka5 c4 15.Kb4 Kd7 16.Kxc4 Ke7 17.Kb5 Ke8 18.c4 Kd7 19.c5 Kc8 20.a4 Kb7 21.c6+ Kb8 22.c7+ Ka7
34/92 01:36 1 567 664k 16 221k +26,55 3. ... c6 4.Nde6+ Kd7 5.h5 a5 6.Kg4 b5 7.Kf3 Kc8 8.Ke3 Kb7 9.Ke4 Ka6 10.Kd4 Kb6 11.b3 c5+ 12.Kd5 c4 13.bxc4 bxa4 14.c5+ Ka7 15.c6 a3 16.c7 Kb7 17.Kd6 Kc8 18.Nd5 Qd2 19.Nd4 Qh6+ 20.e6 Kb7 21.Kd7 Qf8 22.Ne7 a2 23.Nc2 Qe8+ 24.Kxe8 a1R 25.c8Q+ Ka7 26.Nxa1 Kb6 27.Qb8+ Ka6 28.Qa8+ Kb6
34/92 01:36 1 567 664k 16 221k +17,68 3. ... a5 4.Nde6+ Kd7 5.Kg4 Kc6 6.h5 b5 7.b3 Kb6 8.axb5 a4 9.bxa4 Ka5 10.Kf5 Kxa4 11.Nxc7 Qf8+ 12.Ke4 Kb3 13.e6 Qg7 14.Ncd5 Kc2 15.b6 Kd2 16.e7 Qf7 17.Ke5 Qe8 18.Kd6 Qa4 19.Ne6 Ke2 20.Nec7 Qa3+ 21.Kd7 Kf2 22.e8Q Qb3 23.Kc8 Qc2 24.Qf8+ Kg3 25.b7 Kh4 26.b8Q Kxh5 27.Qg8
34/92 01:36 1 567 664k 16 221k +17,22 3. ... Kd7 4.Nde6 Kc6 5.Kg4 a5 6.h5 b5 7.b3 Kb6 8.axb5 a4 9.bxa4 Ka5 10.Kf5 Kxa4 11.Nxc7 Qf8+ 12.Ke4 Kb3 13.e6 Qg7 14.Ncd5 Kb2 15.b6 Qg8 16.e7 Ka1 17.Nf6 Qc4+ 18.Kf5 Qc8+ 19.Kg5 h6+ 20.Kg6 Qxc3 21.e8Q Qg3+ 22.Kf5 Qg5+ 23.Ke4 Qg7 24.Qe5+ Kb1 25.Qb5+ Ka1 26.Qf1+ Ka2 27.Qg2+ Qxg2+ 28.Nxg2 Kb3 29.b7 Ka2 30.b8Q

[Nordlandia]

How long before your engine solve this one

1. Qh6!

No 17931 | G. Amiryan | 3rd honourable mention

[d]5n2/k6p/p1K1p1p1/1pP1P2Q/2p3R1/7b/q1PN3r/8 w - - 0 0

[peter]

This one is rather interesting

Possible cook | Correction: Houdini 5.01 Pro found winning evaluation.

Draw

[d]3k4/2pq3p/pp5R/4P3/P6P/2PN4/1PN3K1/8 w - - 0 0



Analysis - http://www.viewchess.com/cbreader/2017/ ... 04562.html

This one is correct for sure, Jon!

https://glarean-magazin.ch/2009/10/01/s ... n_neghina/

[Nordlandia]

The question is if this one is correct.

[d]8/4k3/3R2KB/P5P1/8/P7/2pp4/1b3R2 w - - 0 0