Does 22.Kc1 draw for white? After 22...a5 23.Qc3 Qa3+ 24.Qb2 axb4 25.c4! is an innovation which has been missed by previous analysis attempts.

We offer main lines and detailed notes (from hundreds of hours of computer time) to organize our thoughts:

22.Kc1 a5(note a1 for 22...Bf5 complications)
23.Qc3(note a2 for 23.Rhg1) Qa3+
24.Qb2 axb4
25.c4 Qc3+(see Section I and notes c, d and e for 25...Bf4+ 26.Kc2; and note h for other 25.moves)
26.Qxc3 bxc3
27.Bg3 Be7(note b for 27...Ba3+)
28.Kc2 Rb2
29.Kxc3 Rxe2
30.Rde1 Rxe1
31.Rxe1 Ba6
32.cxd5 cxd5
33.Ra1 Bc4
34.Ra7 Kf7
35.Rxc7 Ke6
36.Bf4 g5
37.Bd2 h5
38.Be3 Bf6
39.Kd2 Bb5
40.Rb7 Be8
41.Rb6 Kf5
42.Rd6 Bf7 drawn

Alternate main line:

22.Kc1 a5
23.Qc3 Qa3+
24.Qb2 axb4
25.c4 Bf4+
26.Kc2 b3+(Section I below for 26...e3 lines)
27.Kb1 Qa7
28.Bg3 Bh6
29.Rhf1 Bh3
30.cxd5 cxd5
31.Qa1 Qxa1+
32.Kxa1 Ra8+
33.Kb1 g6
34.Rf6 Ra2
35.Bb5 Bg7
36.Rf2 Ra5 drawn

Section I: 22.Kc1 a5

22.Kc1 a5(note a) 23.Qc2 Qa3+ 24.Qb2 axb4 25.c4

Rybka4.1 TB6

25.c4 Bf4+(note b) 26.Kc2 e3(note c) 27.Bg3 Bf5+(note d) 28.Bd3 b3+ 29.Kc1(note e) e2+ 30.Bxf4 exd1Q+ 31.Rxd1 Qf8 32.Bxc7 Bxd3 33.Bxb8 Bc2 and now +0.00/28 34.Bg3(note e)

Notes

note b [-0.50] d=28 25...Qc3+ 26.Qxc3 bxc3 27.Bg3 now [-0.31] d=34 27...Ba3+(note f) 28.Kc2 Rb2+ 29.Kxc3 Rxe2 30.Rb1 Ba6 31.Rb8+ Kf7 32.Rf1+ Kg6 33.Be5 Bxc4(note i) 34.Rg1+ Kf5 35.Rxg7 Re3+ and now: a) [-0.28] d=38 36.Kc2 Bd3 37.Kd1 Rf3 38.Rf7 Kg6 39.Rxf3 exf3 40.Ke1 c5 41.Rb3 Bb4 42.Kf2 Bc2 43.Rxf3 cxd4 44.Bxd4 Be4 45.Rf6 Kg5 46.Rc6 Bd6 47.Ba7 Kf5 48.Bb8 d4 49.Rc4 Bd5 50.Rxd4 Bc5 51.Ke3 b) -0.55/32 36.Kc2 h6 37.Rxc7 Re2+ 38.Kc3 Bb5 (38...Bc1 -0.29/25 39.Rf8+ Kg4) 39.Rf7+ Kg6 40.Rf6+ Kh5 41.Rf5+ Kg4 42.Rf6(note g) Be7 43.Rg8+ Kh5 44.Rf5+ Bg5 45.Bf6 Kg4 46.Re5 Rxh2 47.Bxg5 hxg5 48.Rgxg5+ Kf3 49.Ref5+ Ke2 50.Rg3 Rf2 51.Rxf2+ black has two pawns for the exchange but is likely drawn

note c [-0.22] d=33 26...b3+ 27.Kb1 Qa7 28.Bg3 Bh6 29.Rhf1 Bh3 30.cxd5 cxd5 31.Qa1 Qxa1+ 32.Kxa1 Ra8+ 33.Kb1 g6 34.Rf6 Ra2 35.Bb5 Bg7 36.Rf2 Ra5 37.Be8 Bg4 38.Bf7+ Kh8 39.Rff1 Bxd1 40.Rxd1 Bf6 41.Kb2 Kg7

note d 27...b3+ 28.Kb1 a) -0.02/30 28...Bf5 29.Bd3 Bxd3 30.Rxd3 Qe7 31.Re1 Qe4 (31...dxc4 32.Bxf4 cxd3 33.Bxe3) 32.Qc3 Qf3 33.Rdxe3 Bxe3 34.Rxe3 Qd1 35.Qc1 Qxd4 36.Qe1 h6 37.cxd5 cxd5 38.Be5 Qc4 39.Qe2 and Re8 40.Kb2 Qa4 41.Rxb3 Qd4+ 42.Bxd4 Rxe2+ 43.Kc3 Rxh2 44.Rb7 draw, however 28.Kc1 as in -0.49/29 26...e3 27.Bg3 b3+ 28.Kc1 Qb4 29.Be1 Qa4 30.Bc3 dxc4 31.d5 Bd6 32.Bxg7 Bf5 33.Rhf1 Bg6 34.Bg4 c3 35.Be6+ Kxg7 36.Qxc3+ Kh6 37.Qxe3+ Bf4 38.Qxf4+ Qxf4+ 39.Rxf4 b2+ 40.Kd2 cxd5 41.Bf5 Bxf5 is a good backup b) +0.00/32 28...Qb4 29.cxd5 c5 30.Bxf4 c4 31.Bxe3 c3 32.Qa1 Bb7 33.Bd2 cxd2 34.Qa7 Ra8 35.Qc5 Qa4 36.Kb2 Qa2+ 37.Kc3 Qc2+ 38.Kb4 Qa2 39.Kc3 Qc2+ 40.Kb4 Qa2 perpetual check

note e a) [-0.02] d=27 29.Kc1 e2+ 30.Bxf4 exd1Q+ 31.Rxd1 Qf8 32.Bxc7 Bxd3 33.Bxb8 Bc2 and now +0.00/28 34.Bg3 Bxd1 35.Kxd1 Qf1+ 36.Be1 dxc4 37.Qd2 Qf7 38.Kc1 Qe7 39.Qf2 h6 40.Bc3 Qe6 41.Kb2 Kh7 42.Qf8 Qd5 43.Ka3 Qg2 44.Qf5+ Kh8 45.Qc8+ Kh7 46.Qf5+ Kh8

note f 27...Be7 is playable: [-0.31] d=38 27...Be7 28.Kc2 Rb2 29.Kxc3 Rxe2 30.Rde1 Rxe1 31.Rxe1 Ba6 32.cxd5 cxd5 33.Ra1 Bc4 34.Ra7 Kf7 35.Rxc7 Ke6 36.Bf4 g5 37.Bd2 h5 38.Be3 Bf6 39.Kd2 Bb5 40.Rb7 Be8 41.Rb6 Kf5 42.Rd6 Bf7 white is holding

note g -0.24/30 42...Be7 43.Rg8+ Kh5 44.Rf5+ Bg5 45.Bf6 Re3+ 46.Kb4 Rf3 47.Rxf3 exf3 48.Bxg5 f2 49.Rf8 f1Q 50.Rxf1 Bxf1 51.Bf4 Kg6 52.Kc5 Bb5 53.Kd6 h5 54.Ke5 h4 55.Bd2 h3 56.Ke6 Kh5 57.Kf5 Bd3+

note h a) 25...Bf5 likely goes nowhere: [-0.10] d=28 26.Bg3 Bxg3 27.hxg3 Qe3(note j) 28.Qd2 Qxg3 (28...Qb3 29.Qb2 Qxg3 see note j) 29.Rdg1 Qa3 30.Qb2 e3(note k) 31.Rh5 Be4 32.Re5 Qc3 (32...Ra8 33.Qxa3 bxa3 34.cxd5 cxd5 35.Bb5 Ra7 36.Re7 g5 (36...g6 37.Rf1) 37.Rxg5+ Bg6 38.Rg1 Rb7 39.Rxg6+ hxg6 40.Bc6) 33.Qxc3 bxc3 34.Rxe4 dxe4 35.Rg3 Rd8 36.Rxe3 Rxd4 37.Kc2 c5 38.Rxc3 g6 39.Rg3 Kf7 40.Rg5 h5 41.Rxc5 note that you need to look carefully at the position after 32.Re5 in order to see all this

b) 25...Be6 likely goes nowhere: [+0.00] d=29 25...Be6 26.cxd5 Bxd5 27.Bg3 Qa5 28.Bxd6 cxd6 29.Rhg1 Ra8 30.Kd2 b3 31.Ke3 Qc7 32.Ra1 Rb8 33.h4 Kh8 34.Raf1 Qd7 35.Rg3 Qe7 36.Rf4 Ra8 37.Rg1 Qa7 38.Rgf1 Kg8 39.Rg1 Kh8 40.Rgf1 Kg8

c) 25...Be7 likely goes nowhere: [+0.00] d=30 25...Be7 26.Rhf1 Ba6 27.Kb1 Bf6 28.Bg3 dxc4 29.Qxa3 bxa3 30.Ka1 Rb2 31.Be5 Rxe2 32.Bxf6 gxf6 33.Rxf6 Kg7 34.Rxc6 Bb5 35.Rxc7 Kg6 36.Rb1 Be8 37.d5 Rxh2 38.Re7 Ba4 39.Rg1 Kf5 40.Rf1 Kg6

d) 25...Ba6 likely goes nowhere: [+0.00] d=29 25...Ba6 26.Qxa3 bxa3 27.Bg3 Be7 28.h4 dxc4 29.Bxc7 Rb2 30.Rh2 e3 31.Bf1 Rb3 32.Be5 Bb4 33.Ra2 Bc3 34.Kc2 Bb2 35.Re1 Kf7 36.Bd6 Rc3 37.Kb1 Bc8 38.Rxb2 Bf5 39.Ka1 axb2 40.Kxb2 Rb3

e) 25...g6, 25...h6, 25...Bh3, 25...Bd7 likely go nowhere, as in (for all 4 moves) 26.cxd5 cxd5 27.Bg3 Bxg3 28.hxg3 Qxg3

note i a) 33...Re3+ 1. -0.27/35 34.Kd2 Rd3+ 35.Kc2 Bxc4 36.Rg1+ Kf5 37.Rxg7 h6 38.Rxc7 Rf3 39.Rf7+ Kg4 40.Rg8+ Kh5 41.Rxf3 exf3 42.Bg3 Bd6 43.Bxd6 f2 44.Rf8 f1Q 45.Rxf1 Bxf1 46.Be7 Kg4 47.h4 Kf3 48.Kc3 Ke4 49.Bf8 Bishops of opposite color, drawn, extra pawn is useless 2. -0.27/35 34.Kc2 Bxc4 35.Rg1+ Kf5 36.Rxg7 h6 37.Rxc7 Rf3 38.Rf7+ Kg4 39.Rg8+ Kh5 40.Rxf3 exf3 41.Bg3 Bd6 42.Bxd6 f2 43.Rf8 f1Q 44.Rxf1 Bxf1 45.Be7 Kg4 46.h4 Kf3 47.Kc3 Ke4 48.Bf8 h5 49.Bg7 b) [+0.00] d=22 33...Kh5 34.Rh8 Kh6 35.Rg1 g5 36.Bf6 g4 37.Rg8 c5 38.cxd5 Bb4+ 39.Kb3 Re3+ 40.Kc2 Rc3+ 41.Kb2 Rf3 42.R8xg4 Rf2+ 43.Kb3 Rf3+ 44.Kc2 Rf2+ 45.Kb3 Rf3+ 46.Kc2 Rf2+ 47.Kb3 Rf3+ 48.Kc2 Rf2+ c) 33...c5 [-0.22] d=29 34.Rg1 Kf5 35.cxd5 Re3 36.Kc2 Bd3 37.Kc3 Bb1 38.Kd2 cxd4 39.Bxd4 Rd3 40.Ke2 Ba2 41.Rf1 Kg4 42.Rg1 Kf4 43.Rf1 Rf3 44.Be3 Kf5 45.Rxf3 exf3 46.Kxf3 Bxd5 47.Ke2 g5 48.Rb5 c6 49.Rb7

note j [+0.00] d=31 27...Qe3+ 28.Qd2 Qb3 29.Qb2 Qxg3 30.Rdf1 g6 31.Kb1 e3+ 32.Rxf5 gxf5 33.Bd3 Qf2 34.Qxf2 exf2 35.Rf1 dxc4 36.Bxc4+ Kg7 37.Rxf2 Rd8 38.Rxf5 Rxd4 39.Rc5 h5 40.Kb2 h4 41.Kb3 Re4 42.Kxb4 Kh6 note that the direct 27...Qxg3 transposes: [+0.00] d=30 27...Qxg3 28.Rdf1 g6 29.Kb1 e3+ 30.Rxf5 gxf5 31.Bd3 Qf2 32.Qxf2 exf2 33.Rf1 dxc4 34.Bxc4+ Kg7 35.Rxf2 Rd8 36.Rxf5 Rxd4 37.Rg5+ Kf6 38.Rc5 Ke7 39.Rxc6 Kd7 40.Bb5 Rd5 41.Rc5+ Kd6 42.Rc6+ Ke5

note k 30...h6 likely goes nowhere: [+0.00] d=29 29.Rdg1 Qa3+ 30.Qb2 h6 31.Rf1 Bh7 32.Rhg1 g5 33.Rg2 e3 34.Rd1 Kg7 35.Qxa3 bxa3 36.Bd3 dxc4 37.Bxh7 Kxh7 38.Re1 Rb3 39.Rc2 Kg6 40.Rxc4 a2 41.Kc2 Ra3 42.Rxc6+ Kf5 43.Ra1 g4 44.Rxh6

Section II: 22.Kc1 Bf5

note a1 22...Bf5 needs quite a bit of analysis work [-0.69] d=32 23.Be3 Bxb4 24.cxb4 Rxb4 25.Qc2 Qa3+ 26.Kd2 Rb2 27.Qxb2 Qxb2+ 28.Ke1 and now [-0.33] d=39 28...a5 29.Kf2 Qb4 30.Ra1 h5 31.Rhc1 a4 32.Bxh5 Qb2+ 33.Be2 Bg4 34.Re1 Bxe2 35.Rab1 Qa2 36.Ra1 Qb3 37.Rxe2 and now [-0.38] d=32 37...c5 38.dxc5 a3 39.Raa2 c6 40.h4 Kh7 41.Kg1 Qc3 42.Kg2 Qc4 43.Rad2 Qb3 44.Kh2 Qc3 45.Bd4 Qc4 46.Be3 Qb3 47.Bd4 Qb4 48.Be3 Qb3 49.Bd4 Qb4 50.Be3 Qb3 51.Bd4 Qb4 52.Be3 Qb3 this line involves a queen sacrifice (and material imbalance) which needs to be examined in great detail. However, we can begin to consider that there are no obvious winning lines.

We offer a main line to organize thinking:

22.Kc1 Bf5
23.Be3 Bxb4
24.cxb4 Rxb4
25.Qc2 Qa3+
26.Kd2 Rb2
27.Qxb2 Qxb2+
28.Ke1 a5 (Qa3, Qb4, Qb8 analysis see note a4)
29.Kf2 Qb4
30.Ra1 h5 (Note a3 for 30...h6 -0.25/37)
31.Rhc1 a4
32.Bxh5 Qb2+
33.Be2 Bg4
34.Re1 Bxe2
35.Rab1 Qa2
36.Ra1 Qb3
37.Rxe2 c5
38.dxc5 a3
39.Rd2 Qc3
40.Re1 c6
41.Ree2 Kh7
42.Kg2 Qb3
43.Kg1 Kg6 and white is holding in this demonstration line, which represents a long computer run started at the position prior to 28...a5 and lasted 1756 hours... (depth 39), and scored -0.33. 39.Raa2 is investigated in note a1 above.

note a2 [-0.86] d=31 23.Rhg1 Bf5 24.Be3 Bxb4 25.cxb4 Rxb4 26.Qc3 Qa2 27.Qc2 Qa3+ 28.Kd2 Rb2 29.Qxb2 Qxb2+ 30.Ke1 a4 31.Kf2 Qb4 32.Ra1 h6 33.Rgb1 Qd6 34.Kg1 a3 35.Rb3 c5 36.Rbxa3 Qg6+ 37.Kf1 Qf6 38.Rd1 does not seem to work for white - compare position after 30.Ke1 with note a1 above after 28.Ke1 - but this line just indicates that we should focus efforts on 23.Be3 instead for white

note a3 30...h6 [-0.25] d=37 31.Rhc1 a4 (Bd7 was examined and rejected, likely from this line: [-0.22] d=33 31.Rhc1 Bd7 32.Rcb1 Qd6 33.Kg1 c5 34.dxc5 Qf6 35.Rd1 a4 36.Rd4 Kh7 37.Ra3 Qg6+ 38.Kf2 Qc6 39.Rd2 Qb7 40.Ra1 Be8 41.Rg1 a3 42.Bd4 g6 43.Rf1 Bd7 44.Ke3 Bf5 45.Rc2 Qb3+ 46.Rc3) 32.Rxc6 Qb2 33.Rg1 h5 34.Rcc1 Bg4 35.Rge1 Bxe2 36.Rxe2 Qb8 37.Kg2 Qb5 38.Kf2 Qb6 39.Ra1 Qc6 40.Rea2 Qd7 41.Ke1 h4 42.Ra3 Qd6 43.R1a2 Qb4+ 44.Kf2 Qf8+ 45.Ke1 Qb8 46.Rxa4

note a4 a) [-0.21] d=35 28...Qb8 29.Rf1 Bh3 30.Rg1 a5 31.Rg3 Be6 32.Rc1 Bd7 33.Bd2 g6 34.Bxa5 Qb2 35.Rd1 c5 36.Bc3 Qb6 37.dxc5 Qxc5 38.Be5 Be6 39.Rd2 e3 40.Rd3 Qb4 41.Kf1 Qb1 42.Kg2 c5 43.Rgxe3 d4 b) 28...Qa3 29.Kf2 [-0.27] d=34 29...Qd6 30.Rhg1 a5 ( A. 30...Qxh2+ 31.Rg2  [-0.05]  d=38  31...Qd6 32.Rg3 a5 33.Kg2 a4 34.Rf1 Qd7 35.Ra1 c5 36.dxc5 g6 37.Bd4 Kf8 38.Rh1 Qe7 39.Rf1 Qe6 40.Bb5 Ke7 41.Rf2 Qc8 42.Bxa4 Qa6 43.Bb3 c6 44.Bc2 Qc4 45.Rd2 Qb4 46.Rd1 Qa5 B. 30...c5 -0.16/29 31.dxc5 Qxh2+ 32.Rg2 Qe5 33.Rg3 g6 34.Kg2 Kf7 35.Bd4 Qe8 36.Ra1 Qb8 37.Rga3 Qb4 38.Be5 Qd2 39.R1a2 Qg5+ 40.Bg3 d4 41.Rxa7 Kg7) 31.Kg2 a4 32.Ra1 a3 33.Rgf1 h6 34.Kh1 Bg6 35.Bc1 e3 36.Rxa3 Be4+ 37.Bf3 e2 38.Re1 Qe7 39.Kg2 c5 40.dxc5 d4 41.Rxe2 Bxf3+ 42.Kxf3 Qxc5 43.Re1 Qd6 44.Ra1 Qc6+ c) 28...Qb4 29.Kf2 a5 transposes to the main line or 29...Qd6 to note b) in this section

Conclusions:

1. The main lines 22.Kc1 a5 23.Qc2 Qa3+ 24.Qb2 axb4 25.c4 Qc3+ and 25...Bf4+ do not at this time (January 2014) lead to direct wins for black under deep study. Those who claim a win for black should respond to these lines. 4 other responses to 25.c4 are presented in section h that do not appear to work for black.
2. Notes a-k (especially note a) represent the critical lines and all need to hold in order to claim this line is drawn.
3. I suggest that the modest negative "score" for note a1 is due to a material imbalance which typically favors black but (in this specific case) does not result in an easy-to-find win for black. In endgame positions the scores can become meaningless if they do not point to wins, or to future positions with stronger advantage.