Been here quite a few times as Black
The usual (best IMO) move is 11...Nc5 to which White usually replies 12.f3.
Not sure about 11....Ng4 but I see the idea(s).
It was trap ( 😉 ) Black is hoping White will jump at the chance of
doubling Black pawns on the c-file and isolating the a-pawn and play 12.Nc6.
(trust me once a player reads how weak doubled and isolated pawns are
they will doing anything to inflict them on their opponent.)
So after 12.Nc6 anticipatong 12...cxb6 and Qxg4
Black plays 12...Qh5 with hits on h2 and f2 and the c6 Knight is still
hanging waiting to double and isolate pawns.
The other idea is after h3 if the game swings back to normal lines
with White playimg f3.
Then you can see c6, Nh5, Qf6 and Bxh3 shots appearing.
In the actual game after White played h3 the f-pawn stayed on f2 to
cover g3.
In the game Ndb5 is a good move presenting Black with problems.
Bg5 (hence 12....h6) and Nd5 are floating about, the Black Rooks are
forkable with a Knight on c7.
It cannot be kicked with c7-c6 due to the weak d6 pawn.
Though KID players are always ready to sac this d6 pawn much in the same
way a K.G. player is prepared to toss his f-pawn.
However here is not the time.
Yes Bxh3 looked a gamble but look at the position. (Black to play)
Surface scans and I'm looking at Bxb6 and Rxd6 or Nxd6, then there is
Nxc7 and Nd5 hitting the Queen and b6....maybe...maybe not.
Nd5 and you have the the hit c7.
Now f4 and e5 look good with the d6 pawn pinned and to hell with the hole at g3.
Mix that with some of the combo ideas mentioned earlier and Black is going
to get sqeezed out of the game both positionally and tactically.
Yes ideally you should only attack with you have the superior position
but thanks to the Ng4 experiment that is not going to happen.
Black is not attacking, Black is staying alive.
He has decided OTB not to go down like a whimpering slug but put up a fight.
The art is spotting the moment, leave it too late and it always that.
Too late.
Bxh3 takes the pin off the d6 pawn and the sting from f2-f4 which looks
like a severe threat; It also let's White know he still has his win but
it is not going to be as easy as a positional crush facing no counter play.
Black did not like what he saw coming so pinged a piece at White.
Seen it work 100 times at our level, the spec sac to get back into the game
and cloud the waters.
(Come up and see my score book sometime.)
But White was up for it. It was his day. Good game.