It's a positional error. Nd4 would have led to an equal position. Shirov correctly replied to Nb4 with 23. c3 Na6 14. d4 leaving the Na6 poorly placed, black's b5 pawn a bit weak, white's d pawns controlling central squares and keeping blacks queen side pieces from activating, White can maintain the bind while shifting attention to black's kingside . That said, the position is very complex and both players made mistakes going forward.
Why black horse to b4 was a blunder by computer can anyone explain me?
It's a positional error. Nd4 would have led to an equal position. Shirov correctly replied to Nb4 with 23. c3 Na6 14. d4 leaving the Na6 poorly placed, black's b5 pawn a bit weak, white's d pawns controlling central squares and keeping blacks queen side pieces from activating, White can maintain the bind while shifting attention to black's kingside . That said, the position is very complex and both players made mistakes going forward.
GG
Qe1 fatal error, better was Qh5!!!!!!!!!!! and bye bye....