TalkChess.com

peter wrote: ↑Thu May 09, 2019 12:04 pm

MikeGL wrote: ↑Thu May 09, 2019 10:46 am because I was using my weak smartphone earlier to check those lines, after 36.Nf1 the direct Bxf1 looks incorrect, that's why I traced your PC output just now but the Nb6 (Sb6) on your first post looks not top move of engines, it was only 6th.

(35. Qa1 Na4 36. Nf1 Qe4 37. Rf2 Bxf1 38. Rexf1 Rb3 39. Qa2 Rxc3 40. Re2 Qd3) this is the line I was referring with a win for black. Maybe there were improvements somewhere. This is just the top output of Multi-PV analysis.

Thanks again for showing the position, it's very interesting and can be used well for testing, but 27...Rxc3 isn't a game changing single one best move, and it's drawn.

You're correct, Rxc3 is good, but winning the game was just a plus, most important is getting out of passive position due to bad bishop of black.
That exchange sac also put black into a sure draw and a possible win just like AdminX post showing =/+ for black. Rxc3 is needed for the bad bishop to reposition at Bb5 and activate this bad piece.

peter wrote: ↑Thu May 09, 2019 12:04 pm

MikeGL wrote: ↑Thu May 09, 2019 10:46 am because I was using my weak smartphone earlier to check those lines, after 36.Nf1 the direct Bxf1 looks incorrect, that's why I traced your PC output just now but the Nb6 (Sb6) on your first post looks not top move of engines, it was only 6th.

(35. Qa1 Na4 36. Nf1 Qe4 37. Rf2 Bxf1 38. Rexf1 Rb3 39. Qa2 Rxc3 40. Re2 Qd3) this is the line I was referring with a win for black. Maybe there were improvements somewhere. This is just the top output of Multi-PV analysis.

Don't see an output- line of mine with 37...Bxf1 but after 35. Qa1 Na4 36. Nf1 Qe4 37. Rf2 Bxf1 38. Rexf1 Rb3 39. Qa2 Rxc3 40. Re2 Qd3 it's drawn still.

8/2k5/3p4/p2p1p2/n2P1Pp1/P1rqP1Pp/Q3R2P/5RK1 w - - 0 1

Analysis by CF EXT 060519 x64 POP NUMA:

41.Rfe1 Rb3 42.Qc2+ Qxc2 43.Rxc2+ Kd8 44.Rec1 Nb6 45.Rc7 Nc4 46.Ra7 Rb2 47.Kh1 Kc8 48.Rf7 a4 49.Rxf5 Kd7 50.Rg5 Nd2 51.f5 Ke7 52.Rg8 Kf6 53.Rgc8 Ne4 54.R1c2 Rb3 55.R2c7 Kxf5 56.Kg1 Nd2 57.Kf2 Nc4 58.Re8 Rb2+ 59.Ke1 Nxa3 60.Rf7+ Kg6 61.Rff8 Rxh2 62.Rg8+ Kh7 63.Rh8+ Kg7 64.Rhg8+
= (0.00) Depth: 55/47 00:04:03 5867MN

Till I see a real winning line by myself or from anybody else, I'm outa here, Mike.

Thanks again for showing the position, it's very interesting and can be used well for testing, but 27...Rxc3 isn't a game changing single one best move, and it's drawn.

Again, CF is showing incorrect lines, after 41.Rfe1 above, 41...Rb3 is not optimum but 41...Nb6! with a possible winning line.
This is Multi-PV with the best move and ends with a 0-1
If you follow the Multi-PV of AB engine you would agree, that below line is all top moves, and ends in a win for black.

[pgn] [Event "?"] [Site "?"] [Date "2019.05.09"] [Round "?"] [White "SF10"] [Black "SF10"] [Result "*"] [BlackElo "2400"] [WhiteElo "2400"] [TimeControl "5400+5"] [SetUp "1"] [FEN "8/2k5/3p4/p2p1p2/n2P1Pp1/P1rqP1Pp/Q3R2P/5RK1 w - - 0 1"] [Termination "unterminated"] [PlyCount "17"] 1. Rfe1 Nb6 2. Qb2 Rb3 3. Qc2+ Qxc2 4. Rxc2+ Nc4 5. a4 Ra3 6. Rcc1 Rxa4 7. Ra1 Rb4 8. Rab1 Kb6 9. Kf2 {-+} [/pgn]

MikeGL wrote: ↑Thu May 09, 2019 12:39 pm Again, CF is showing incorrect lines, after 41.Rfe1 above, 41...Rb3 is not optimum but 41...Nb6! with a possible winning line.
This is Multi-PV with the best move and ends with a 0-1
If you follow the Multi-PV of AB engine you would agree, that below line is all top moves, and ends in a win for black.

[pgn] [Event "?"] [Site "?"] [Date "2019.05.09"] [Round "?"] [White "SF10"] [Black "SF10"] [Result "*"] [BlackElo "2400"] [WhiteElo "2400"] [TimeControl "5400+5"] [SetUp "1"] [FEN "8/2k5/3p4/p2p1p2/n2P1Pp1/P1rqP1Pp/Q3R2P/5RK1 w - - 0 1"] [Termination "unterminated"] [PlyCount "17"] 1. Rfe1 Nb6 2. Qb2 Rb3 3. Qc2+ Qxc2 4. Rxc2+ Nc4 5. a4 Ra3 6. Rcc1 Rxa4 7. Ra1 Rb4 8. Rab1 Kb6 9. Kf2 {-+} [/pgn]

Multi- or sinlge pv, could you please start doing some Backward with you lines of "top moves" before simply taking them for granted, just because at short hardware-time they are assorted top of the list of arbitrarily chosen number of primaries, dear Mike?


After 7(47) Ra1?:

8/2k5/3p4/p2p1p2/r1nP1Pp1/4P1Pp/7P/R3R1K1 b - - 0 1

Analysis by CF EXT 060519 x64 POP NUMA:

47...Rb4 48.Rab1 Nd2 49.Rbc1+ Kb6 50.Kf2 Rb2 51.Re2 a4 52.e4 Nxe4+ 53.Ke1 Rb3 54.Rec2 Kb5 55.Rc7 Kb4 56.Rf7 Nc3 57.Kd2 Nb5 58.Rxf5 Rb2+ 59.Kd3 a3 60.Rxd5 a2 61.Ra1 Rxh2 62.Rg5 Rg2 63.Rxg4 h2 64.Rh4 d5 65.Ke3 Rxg3+ 66.Kf2 Rg1 67.Rxa2 h1Q 68.Rxh1 Rxh1 69.Ra6 Nxd4 70.Kg2 Rh8
-+ (-4.07) Depth: 37/64 00:00:40 1051MN

Before that blunder:

8/2k5/3p4/p2p1p2/r1nP1Pp1/4P1Pp/7P/2R1R1K1 w - - 0 1

Analysis by CF EXT 060519 x64 POP NUMA:

47.Kf2 Rb4
-+ (-2.06 --) Depth: 48/84 00:01:29 2165MN

Still losing, but not at once as after your "top move".

After 6(46). Rcc1?:

8/2k5/3p4/p2p1p2/P1nP1Pp1/r3P1Pp/7P/2R1R1K1 b - - 0 1

Analysis by CF EXT 060519 x64 POP NUMA:

46...Rxa4 47.Kf2 Rb4 48.Rb1 Na3 49.Ra1 Rb3 50.Rec1+ Kd7 51.Kg1 Rxe3 52.Ra2 Nc4 53.Raa1 Rb3 54.Rcb1 Rd3 55.Rd1 Rc3 56.Rdb1 Kc6 57.Rc1 Rd3 58.Rxa5 Rxd4 59.Ra6+ Kc5 60.Ra5+ Kb6 61.Ra2 Rd3 62.Rac2 Kc5 63.Kf2 Rb3 64.Ke1 Kd4 65.Ke2 Re3+ 66.Kf2 Ra3 67.Ke1 Rd3 68.Ra1 Rb3 69.Rd1+ Ke4 70.Rdc1 Rb4 71.Kf2 Ne3 72.Rd2 d4 73.Re1 Rb3 74.Ra2 Rc3 75.Ra4 Kd5 76.Ra5+ Kc4 77.Ra2 Kc5 78.Ra5+ Kb4 79.Ra2 Nc4 80.Rb1+ Kc5
-+ (-2.62) Depth: 48/66 00:01:04 1671MN

Before this one blunder:

8/2k5/3p4/p2p1p2/P1nP1Pp1/r3P1Pp/2R4P/4R1K1 w - - 0 1

Analysis by CF EXT 060519 x64 POP NUMA:

46.Rb1 Rxa4 47.Rcc1 Kd7 48.Rb7+ Kc6 49.Rb8 Ra3 50.Re1 Nxe3 51.Reb1 Nc4 52.Rc8+ Kd7 53.Ra8 Nd2 54.Ra7+ Kc6 55.Ra6+ Kc7 56.Ra7+
= (0.00) Depth: 58/21 00:03:24 5015MN

Notice, if you're analysing in mv mode, you have to give even more hardware- time to get later in line arising moves into correct calculation and evaluation, the broader the plies are searched with primary or with non primary- variant parameters, is the less deeper it gets in same time.

Otherwise of course nobody would let any engine play in single variant mode, but always only with as much multiple primary lines as possible.

If you play out or analyse forward in mv-mode, you don't have to be surprised, if blunders arise with not deep enough search. That the side, that has to defend against losing, is blundering first and more often than the attacking one, is chess- immanent.

All that might be not as true as for MCTS as for A-B-search, as komodo MCTS shows, but analysing with SF, you should be aware of it and at least give the lines a Backward, before you think them to best for sure,

To keep longer lines in hash, especially the ones, you found in mv- mode only, single variant mode will be faster for that even more.

MikeGL wrote: ↑Thu May 09, 2019 12:19 pm You're correct, Rxc3 is good, but winning the game was just a plus,

Yes, a plus based on White blundering.

Peter, have you seen my PM end of april?

Paloma wrote: ↑Thu May 09, 2019 1:52 pm

Oops, sorry, but no. I fear I've deleted it by mistake, thinking it to be an older one, I had already answered.
Can you send again, please?

MikeGL wrote: ↑Thu May 09, 2019 10:41 am

chrisw wrote: ↑Thu May 09, 2019 9:58 am Neither has this line been refuted...

e4 is absolute key move, cutting blacks ability to pivot on that square.

30. Ra1 Bd3 31. e4 dxe4 32. Qa4 Nb3 33. Ra2 is better than the above Rad1 (which threatens nothing and allows black to improve his position)

after 33. Ra2 Nc1 is just drawing, Nc5 also a draw. NxN is draw, some positions are like your line, but a vital tempo ahead (various defences, including Ke3 and counter exchange sac, the tempo is important here)
a6 would be an attempt to keep pieces on the board, but it isn't enough and the position holds, I think.

Key was e4, it gave the king a blockade square on e3, prevented the mating threat lines with Qe4 and gained just enough time. Therefore draw, not decisive black win by strangulation.

I traced this and too many 0.00 but strange how I got +score for black at the end, maybe there are improvements here:
30. Ra1 Bd3 31. e4 dxe4 32. Qa4 Rb2 33. Qxa5 Rxd2+ 34. Ke3 Rb2 35. Qd8+ Kb7 36. Rad1 Rb3 37. Rxd3 Qc4 38. Red1 exd3 39.
Qxd6 d2 {-/+}
If you check with multi-pv infinite you would agree that I just traced and followed the top moves for white but ended a win for black.
Maybe some drawing lines are hidden.

If you analyse with a computer you’re not going to find the key moves. Computers don’t find e4 in the first place, that requires human analysis, or put it another way, I can’t persuade SF10 to find it within time frame.

peter wrote: ↑Thu May 09, 2019 2:07 pm

Hi Peter,
regarding your PM -> 6 was correct ; Oh my God

chrisw wrote: ↑Thu May 09, 2019 2:50 pm

MikeGL wrote: ↑Thu May 09, 2019 10:41 am

chrisw wrote: ↑Thu May 09, 2019 9:58 am Neither has this line been refuted...

e4 is absolute key move, cutting blacks ability to pivot on that square.

30. Ra1 Bd3 31. e4 dxe4 32. Qa4 Nb3 33. Ra2 is better than the above Rad1 (which threatens nothing and allows black to improve his position)

after 33. Ra2 Nc1 is just drawing, Nc5 also a draw. NxN is draw, some positions are like your line, but a vital tempo ahead (various defences, including Ke3 and counter exchange sac, the tempo is important here)
a6 would be an attempt to keep pieces on the board, but it isn't enough and the position holds, I think.

Key was e4, it gave the king a blockade square on e3, prevented the mating threat lines with Qe4 and gained just enough time. Therefore draw, not decisive black win by strangulation.

I traced this and too many 0.00 but strange how I got +score for black at the end, maybe there are improvements here:
30. Ra1 Bd3 31. e4 dxe4 32. Qa4 Rb2 33. Qxa5 Rxd2+ 34. Ke3 Rb2 35. Qd8+ Kb7 36. Rad1 Rb3 37. Rxd3 Qc4 38. Red1 exd3 39.
Qxd6 d2 {-/+}
If you check with multi-pv infinite you would agree that I just traced and followed the top moves for white but ended a win for black.
Maybe some drawing lines are hidden.

If you analyse with a computer you’re not going to find the key moves. Computers don’t find e4 in the first place, that requires human analysis, or put it another way, I can’t persuade SF10 to find it within time frame.

If your main line contains dumb white move, then you can prove anything, I suppose. In your mainline position, there's no need to commit the Qd8+ abandoning the protection of a3 and c3 (allowing your mainline to work).
White simply plays Ra1d1. Then what? The threat is Rd2 exchanging rooks and then the perpetual is on.
Qa2 allows perpetual anyway.
Qc4 Rd2 Rxd2 perpetual again
Qc4 Rd2 Rb3 perpetual again
Qc4 Rd2 Rb6 Rc1 careful black might lose, probably a draw, but white has solved his problems by now.

Basically your main line is wrong with Qd8+ because black will play a later Rb3 with tempo and the wQ is in the wrong place and has no more checks.

This remains a draw. No black win by strangulation or by anything else. Contrary to computer multipv analysis.

[d]1k6/p7/3pq3/Q4p2/3PpPp1/P1PbK1Pp/1r5P/R3R3 w - - 2 35

Paloma wrote: ↑Thu May 09, 2019 8:11 pm Oh my God