39... C4?? checkmate is now unavoidable
In the 30 turns that follow in my game log, "Lost forced checkmate sequence" appears 5 times. I eventually won, but it was painful.
Any idea why stock fish wants Nh3? (and yes, i checked show moves -- stock fish wants the knight to end up on f4 and thinks that gives an evaluation of about 1.35 v. 1.00 the end of the line with Nf3).