PawnSac: < Helios727: So why the resignation when down only a pawn in a complicated position? >
The answer to that is simple. Black was psychologically defeated. Now, before you think this is an overly simplistic explanation, consider this: It is absolutely true. One gives up when he believes it is hopeless/pointless to continue. Therefore the question is.. On what basis did black conclude it was pointless to continue? OK, lets first consider the facts...
1. Black is a 35 yr old master(?) facing a 19 yr old rising star (a GM this year) who no doubt has a reputation and is known as a powerful player.
2. black is technically 1 pawn down, but 3 of his pawns guard the king. White has 2 to blacks 3 on the kingside, and blacks 3 is pretty static/tied down and on white squares, while white has a light squared bishop. On the queenside white has a passer duo which is pretty unstoppable in an endgame.
3. white has the 2 bishops advantage.
4. white has the tactical shots..
a. the pin of Nd6
b. the threat of Nd4-Nb5 or Nd4-Nc6 and c5,
c. black's Nh7 is poorly placed / passive and black has no clear tactical counter play and will be completely on the defensive.. and so on.