| AylerKupp: <<Brenin> Does Black have anything better?> (part 1 of 2) If you mean instead of 12...g5 cutting off the Nf6 from its queen's protection then apparently Black has many better moves in reply to 12.Qd3, at least according to Stockfish 13. But Black's game is still very difficult. At d=49 Stockfish indicates that Black's best reply to 12.Qd3 is 13...Be3, which it evaluates at [+2.13], and I consider anything above[1.99] to be likely winning. Stockfish gives Black's best line with best play by both sides to be: 12...Be3 13.Nxf4 Bxd2 14.Qxd2 d6
click for larger view White, in compensation for his pawn deficit, has a great lead in development and his king is safe. 15.Rae1 Rxe1 16.Rxe1
click for larger view White now has 5 pieces developed to Black's 2, and generally 3 tempi are considered sufficient compensation for a pawn deficit, so the position is at worst even from a material standpoint. 16...Nc6 17.Ne4 Bd7 18.Nxf6 gxf6 19.Rf1 Kc8 20.Qd5
click for larger viewI thought that 20.Qc3 might have been better, potentially targeting the Pf6 after the Nf4 moves. And, while at low ply Stockfish evaluates 20.Qd5 as best, by d>32 Stockfish considers both moves to be equally good, evaluating both at > [3.00], but neither as good as 20.Rf3 bringing the rook into play with many attacking possibilities, evaluating it > [+4.00] 20...a5 21.Qg8+ Nd8 22.Qf8 a4 23.h3 Ra5 24.Ne6 f5 25.Kh2 Bxe6 26.Bxe6+ Kb8 27.Bxf5 Ka7 28.Bd3 Nc6 29.Qf7 a3 30.bxa3 Qd8 31.Qxh7
click for larger viewBlack has given up 2 pawns in its last 2 moves. Why? The Pa3 will likely fall but the loss of the h-pawn will be problematic for Black. 31...Ne5 32.Qg7 Rc5 33.Rf4 Qe8 34.Bf5 Rc3 35.h4
click for larger viewIt seems to me that White can now win simply by advancing its h-pawn 35...Qh5 36.Qg5 Qh8 37.h5 Nf7 38.Qh4 Rc5 39.Bg4 Ne5 40.Bh3 Rxc2 41.h6 Re2 42.Bf5 Rxa2 43.h7 Rxa3 44.Rf1
click for larger viewThis seems incomprehensible to me. How does this help advancing the h-pawn? Why not 44.Qg5 threatening 45.Qg8? Or even 44.Be4 threatening 45.Rf8?) 44...Ra5 45.Kh3 c5 46.Qg5 (Finally)
click for larger viewBlack is still lost but Stockfish has not managed to substantially improved White's position since contain distance to mate (DTM) information. So, faced with multiple lines that indicate a win, the engines don't know which line is best; i.e. which one leads to the shortest mate. So they can only pick a line at random or, more accurately, likely the line that first shows up in its search tree transversal at a given search depth. | 
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