Mate in 3 that I missed

What about it?

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).

100% should have lost this

Why is this an invalid notation?

Why is this a brilliant? I’m only 300 elo

I managed to checkmate by promotion for the first time and with a knight!!

Cool Mate in 9 that I found in game

First Brilliant move!

Why is this brilliant

What about it?

I took pawn with bishop

Nice little knight and pawn checkmate, I’ve not seen one like this before

Find the best move?!