Revisiting Nolot Problems

[induktio]

http://en.wikipedia.org/wiki/Nolot

Take a look at the problem #6:
rnbqk2r/1p3ppp/p7/1NpPp3/QPP1P1n1/P4N2/4KbPP/R1B2B1R b kq - 0 1

13... axb5!! offers a rook to keep the white queen out of play. 14.Qxa8 Bd4 15.Nxd4 cxd4 16.Qxb8 0-0! 17.Ke1 Qh4 18.g3 Qf6 19.Bf4 g5? (Ivanchuk found 19...d3! during post-game analysis.) 20.Rc1 exf4 21.Qxf4 Qd4 22.Rd1 bxc4 23.e5 Qc3+ 24.Rd2 Re8 25.Bxd3 cxd3 -+

Tasc R30 finds 19... d3! in 2 1/2 hours. 19... Bf5!! is even stronger than 19... d3.

Now, this is probably the hardest problem of them all. So here's Crafty 23.4 analysis:

Code: Select all

29   591:43   1.23   1. ... Bd7 2. h3 Bd4 3. Nfxd4 cxd4
		    4. hxg4 Qb6 5. Ke1 O-O 6. g5 Qg6 7.
		    Bd3 axb5 8. Qxa8 bxc4 9. Bxc4 Qxe4+
		    10. Kf2 d3 11. Be3 Qf5+ 12. Kg3 Qg4+
		    13. Kh2 Qh4+ 14. Kg1 Qxc4 15. Qxb7
		    e4 16. Kf2 Qc2+ 17. Kg3 Qe2 18. Bc5
		    (s=9)
29   770:36     -1   1. ... axb5!
29   1061:39   1.05   1. ... axb5 2. Qxa8 Bd4 3. Ra2 Qc7
		    4. Kd1 O-O 5. cxb5 Nf2+ 6. Rxf2 Bxf2
		    7. Qa4 cxb4 8. Qxb4 Bg4 9. Bb2 Rc8
		    10. Bd3 Nd7 11. Qd2 Qb6 12. h3 Bxf3+
		    13. gxf3 Be3 14. Qb4 Nc5 15. Bc4 Qd6
		    16. Ke1 (s=7)
29-> 1260:45   1.05   1. ... axb5 2. Qxa8 Bd4 3. Ra2 Qc7
		    4. Kd1 O-O 5. cxb5 Nf2+ 6. Rxf2 Bxf2
		    7. Qa4 cxb4 8. Qxb4 Bg4 9. Bb2 Rc8
		    10. Bd3 Nd7 11. Qd2 Qb6 12. h3 Bxf3+
		    13. gxf3 Be3 14. Qb4 Nc5 15. Bc4 Qd6
		    16. Ke1 (s=2)
30   1523:17   1.10   1. ... axb5 2. Qxa8 Bd4 3. Ra2 Qc7
		    4. Kd1 O-O 5. cxb5 Nf2+ 6. Rxf2 Bxf2
		    7. Qa4 cxb4 8. Qxb4 Bg4 9. Bd3 Nd7
		    10. h3 Nc5 11. Be2 Bxf3 12. Bxf3 Bd4
		    13. Rf1 Nd3 14. Qb1 Rc8 15. Bd2 Nb2+
		    16. Ke1 Qc4 17. Bg4
30-> 3311:28   1.10   1. ... axb5 2. Qxa8 Bd4 3. Ra2 Qc7
		    4. Kd1 O-O 5. cxb5 Nf2+ 6. Rxf2 Bxf2
		    7. Qa4 cxb4 8. Qxb4 Bg4 9. Bd3 Nd7
		    10. h3 Nc5 11. Be2 Bxf3 12. Bxf3 Bd4
		    13. Rf1 Nd3 14. Qb1 Rc8 15. Bd2 Nb2+
		    16. Ke1 Qc4 17. Bg4 (s=6)

Crafty seems to think 15.Nxd4 is inferior to Ra2, and 16.Qxb8 is a slight mistake. That is, after 14...Bd4 Crafty seems to prefer entirely different lines than those on the wiki page. Any other engines agree? Be2 Bxf3 12

[zullil]

30-> 3311:28 1.10 1. ... axb5 2. Qxa8 Bd4 3. Ra2 Qc7
4. Kd1 O-O 5. cxb5 Nf2+ 6. Rxf2 Bxf2
7. Qa4 cxb4 8. Qxb4 Bg4 9. Bd3 Nd7
10. h3 Nc5 11. Be2 Bxf3 12. Bxf3 Bd4
13. Rf1 Nd3 14. Qb1 Rc8 15. Bd2 Nb2+
16. Ke1 Qc4 17. Bg4 (s=6)
[/code]
Crafty seems to think 15.Nxd4 is inferior to Ra2, and 16.Qxb8 is a slight mistake. That is, after 14...Bd4 Crafty seems to prefer entirely different lines than those on the wiki page. Any other engines agree? Be2 Bxf3 12

Is that correct? You ran Crafty for 55 hours?

Here's what Critter-1.4 (8 threads) gives after about 1 hour:

Code: Select all

23/67  59:31 32583304138 9124195  +0.00 axb5 Qxa8 Qc7 Rb1 Bd4 bxc5 Bxc5 Rxb5 Nd7 Qa4 O-O Qc2 f5 exf5 e4 Ng5 Rxf5 Ke1 Ndf6 Be2 Bf2+ Kd1 Bd4 Nh3 Ne3+ Bxe3 Bxe3 g4 Re5 Qb3 Rxd5+ Rxd5 Nxd5 Nf2 Qc5 Nxe4 Qd4+ Qd3 Qa1+ Kc2 Qa2+ Kd1 Qa1+

I'll let the search continue for a while.

[ernest]

Crafty seems to think 15.Nxd4 is inferior to Ra2,

Nolot himself thinks that after 15.Ra2, Position 6 is a draw

[zullil]

30-> 3311:28 1.10 1. ... axb5 2. Qxa8 Bd4 3. Ra2 Qc7
4. Kd1 O-O 5. cxb5 Nf2+ 6. Rxf2 Bxf2
7. Qa4 cxb4 8. Qxb4 Bg4 9. Bd3 Nd7
10. h3 Nc5 11. Be2 Bxf3 12. Bxf3 Bd4
13. Rf1 Nd3 14. Qb1 Rc8 15. Bd2 Nb2+
16. Ke1 Qc4 17. Bg4 (s=6)
[/code]
Crafty seems to think 15.Nxd4 is inferior to Ra2, and 16.Qxb8 is a slight mistake. That is, after 14...Bd4 Crafty seems to prefer entirely different lines than those on the wiki page. Any other engines agree? Be2 Bxf3 12

Is that correct? You ran Crafty for 55 hours?

Here's what Critter-1.4 (8 threads) gives after about 1 hour:

Code: Select all

23/67  59:31 32583304138 9124195  +0.00 axb5 Qxa8 Qc7 Rb1 Bd4 bxc5 Bxc5 Rxb5 Nd7 Qa4 O-O Qc2 f5 exf5 e4 Ng5 Rxf5 Ke1 Ndf6 Be2 Bf2+ Kd1 Bd4 Nh3 Ne3+ Bxe3 Bxe3 g4 Re5 Qb3 Rxd5+ Rxd5 Nxd5 Nf2 Qc5 Nxe4 Qd4+ Qd3 Qa1+ Kc2 Qa2+ Kd1 Qa1+

I'll let the search continue for a while.

Here's more:

Code: Select all

26/67  224:36 126243364307 9367607  +0.00 axb5 Qxa8 Qc7 Rb1 Bd4 bxc5 Bxc5 Rxb5 Nd7 Qa4 O-O Qc2 f5 h3 Nf2 Rxc5 Nxc5 Kxf2 fxe4 Be3 b6 Be2 exf3 gxf3 e4 f4 Rxf4+ Bxf4 Qxf4+ Kg2 e3 Rf1 Qg5+ Kh2 Qe5+ Kg2 Qg5+

[induktio]

Is that correct? You ran Crafty for 55 hours?

Here's what Critter-1.4 (8 threads) gives after about 1 hour:

Code: Select all

23/67  59:31 32583304138 9124195  +0.00 axb5 Qxa8 Qc7 Rb1 Bd4 bxc5 Bxc5 Rxb5 Nd7 Qa4 O-O Qc2 f5 exf5 e4 Ng5 Rxf5 Ke1 Ndf6 Be2 Bf2+ Kd1 Bd4 Nh3 Ne3+ Bxe3 Bxe3 g4 Re5 Qb3 Rxd5+ Rxd5 Nxd5 Nf2 Qc5 Nxe4 Qd4+ Qd3 Qa1+ Kc2 Qa2+ Kd1 Qa1+

I'll let the search continue for a while.

Yeah, it's correct Crafty ran that long. A little crazy, I know.

Since your analysis indicates it's a draw, it's not just 15. Ra2 that draws...