Why is ...d5 the best move for Black? I am learning chess and came across this position. Stockfish 11+ HCE (Depth 32/99) and Stockfish 13 (Depth 31/47) both says ...d5 is the best move for Black. But the next move is exd6 e.p., leaving White's pawn at d6, defended by the e4-Knight and Queen, so Black cannot recapture it immediately with Bxd6.
Following along with the engine, Black doesn't really attacks the d6-pawn until at least 10+ moves later. So why did the engine suggest Black sacrifice the only central pawn it has for no apparent reason (at least to me)?
[FEN &quot;r1bqkbnr/pp1p2pp/8/1p2P3/4N3/8/PPP2PPP/R1BQK2R b KQkq - 0 8&quot;]
1. e4 e5 2. Nf3 Nc6 3. Bb5 f5 4. d4 fxe4 5. Nxe5 Nxe5 6. dxe5 c6 7. Nc3 cxb5 8. Nxe4
10+ moves later is enough! Note that material-wise, Black is already winning. The sacrifice Nc3 is far too speculative. What is the worst thing that could happen to Black? Nd6+, walling him in, or even followed by some Re1+ after exchange on d6. Thus, rather sacrifice a pawn while White hasn't even castled, than allow any swindles.