Quiz answer

Here's the answer to the quiz that I flunked in over-the-board play:

Hayhurst-Brock

Chicago Industrial Chess League, 2011

After 71...g5: White to play and win

It would have been time for me to throw in the towel after the simple but difficult 71.hxg5! hxg5 72.Nd5!   It would have been a well-deserved victory for the Bh3, which had been engaged in a domination struggle with the Ne3 for a couple dozen moves.

Both players knew that White could not afford to trade away all his pawns, so we both overlooked that in certain situations, White might want to initiate the trade.  (Hayhurst was in severe time pressure, but I had a good twenty minutes.)