Test Position and a Shootout

What Should Black Play?

This is a position that could have been reached in one of my correspondence games.  I was Black and it’s my move.  Should I retreat with 19…Bg6 or should I play 19…Bxf3 with the following moves: 20.gxf3 Qg3+ 21.Kf1 Qxf3+ 22.Ke1 Qxh3 reaching the following position:

Here are the engine evaluations after 3 minutes:

FireBird 1.2X64 =(0.22)

Houdini 1.5x64 +/=(0.41)

Fritz 12 +/=(0.59)

I think I would go with Fritz 12 on this one, but what do I know?!  My thinking was that when Black starts advancing his P’s he is going to leave his K exposed to attack. To confirm my thoughts I did a 5-game shootout using Fritz 12.  White scored 4 wins and one draw.  I decided to try FireBird because I think it’s a stronger engine and also it was more conservative in its evaluation.  The results using FireBird: two White wins out of 2 games.

The conclusion is what we already knew when it comes to materially unbalanced positions.  You can’t always rely on their evaluations.  This is an important point to keep in mind because it seems to me that quite often engines will plunge into these positions thinking they have an advantage, but because engines are materialistic, they often turn out to be wrong.