Arasan 19.0 + updated test suite

[jdart]

I have taken a somewhat unsystematic look at some of the more difficult or unclear ones:

I think this one:

r1q2k1r/ppp2ppp/4n3/3N4/2B5/3Q4/Pb3PPP/4RRK1 w - - bm Rxe6; id "arasan19.50"; c0 "Akopian-Ramaswamy, Gilbraltar Masters 2007";

is problematic because it looks like Re2 might be nearly as good as Rxe6 (but I am not sure).

This one:

8/4nk2/1p3p2/1r1p2pp/1P1R1N1P/6P1/3KPP2/8 w - - bm Nd3; id "arasan19.156"; c0 "Grandelius-Raznikov, EU Youth Chess Ch B18, Albena 2011";

is very hard but the solution is correct. Komodo just does not seem to see it but if you force Nd3 then all of a sudden it gives a big score

2r2rk1/1b2bppn/1qp1p2p/p5N1/PpBPP2P/1P6/1BQ2PP1/1K1R3R w - - bm f4; id "arasan19.75"; c0 "Goloschapov-Skatchkov, Moscow 2004";

f4 is good but I am not sure it beats out all the alternatives by a large margin.

8/3n4/1p1k1p2/p5p1/PP4P1/2B3K1/8/8 b - - bm b5; id "arasan19.136"; c0 "Spassky-Karpov, Leningrad cm(6) 1974";

In my testing so far Stockfish prefers axb4 but Komodo likes b5.

r4rk1/p1p3pp/1pPppn1q/1P1b1p2/P2Pn3/4PN2/1B2BPPP/R2Q1RK1 b - - bm Ng4; id "arasan19.152"; c0 "Korchnoi-Simagin, Soviet ch-27 Leningrad 1960";

This one also seems murky at first but I actually ran it overnight with Komodo and it appears Ng4 is best.

The endgame studies are hard but I don't think they are incorrect, but there is some chance they are. Engines have a real hard time with these (probably due to null move but maybe due to other pruning they do).

--Jon

[Vinvin]

I have taken a somewhat unsystematic look at some of the more difficult or unclear ones:
...
8/3n4/1p1k1p2/p5p1/PP4P1/2B3K1/8/8 b - - bm b5; id "arasan19.136"; c0 "Spassky-Karpov, Leningrad cm(6) 1974";

In my testing so far Stockfish prefers axb4 but Komodo likes b5.
...

axb4 and b5 seem draw both :

Code: Select all

Stockfish_160621_x64_modern_fast:
 62/75	04:25	 3 056 252k	11 532k	 0,00	1. ... b5 2.bxa5 bxa4 3.Bb4+ Kc6 4.Be7 Kb5 5.Kf3 Kxa5 6.Ke4 Kb5 7.Kd5 Nb6+ 8.Kd4 f5 9.gxf5 g4 10.f6 g3 11.Ke3 Nd7 12.Kf3 g2 13.Kxg2
 63/75	04:25	 3 056 252k	11 532k	-0,25	1. ... axb4 2.Bxb4+ Ke6 3.a5 bxa5 4.Bxa5 Kf7 5.Bc3 Ne5 6.Bd4 Ke7 7.Bc3 Kd6 8.Bb4+ Kd5 9.Ba5 Nc6 10.Bc3 Ke6 11.Kf3 Ne5+ 12.Kg3 Nc4 13.Bd4 Nd6 14.Bb2 Ne4+ 15.Kh3 Nc5 16.Kg3 Nb3 17.Bc3 Nc1 18.Kf3 Nd3 19.Kg3 Nf4 20.Ba5 Kd5 21.Kf3 Kd4 22.Bb6+ Kd3 23.Bc5 Ng6 24.Ba3 Ne5+ 25.Kg3 Ke4 26.Be7 Nd7 27.Bd8 Ke5 28.Ba5 Kd6 29.Bc3 Kc7 30.Ba5+ Kc6 31.Kh3 Kb5 32.Bd8 Kb4 33.Kg3 Kc4 34.Kf3 Kd3 35.Kg3 Kc3 36.Be7 Kc4 37.Bd8 Kd3 38.Kf3