In light of the subsidiary threat of ...Bxb3; Rxb3; ...Nd4!, after 16...Bg5, White may need to take some radical measures, however:

Perhaps 17 h4! Bh6 18 g4 ( intending, if 18...Bxb3, 19 g5!) It dumps the g-pawn after just 18...Bxe3+, of course, but remember White is already up a pawn, and Black is opening the g-file.

Not to make excuses, but I was rushing to work at the time.

If 18.Bxg5, 18...Bxb3 19.Rxc6 Qxc6 20.Be3 Bd5.

What SHOULD Robson have done?

He could have played 10 f4, rather than 10 0-0-0. This would have forced 10...d6, tho this still favors Black, because Qe2 sucks. That needs to already be on f3 now. You don't want to play 10...d5? after 10 f4, because you'll get reamed after 11 e5 Nd7 12 Qh5 f6 13 Bd3 g6.

Here, White doesn't need to sac - tho that's devastating - he can also play 14 Qh6, and after 14...f5 15 g4.

Given only one more move, tho, suddenly ...f6! becomes quite viable, as Yermo no doubt noticed.

Let's see...

Yet 10 f4 d6! is favorable for Black pretty much for the reason I've stated. Plus about...five more!

Yes...That's about how many points the upcoming move ...b5! will have.

Let's count them:

Chuck, you're welcome to sit in here, as I give the students their education:

...b5 will:

(1) Open the b-file against White's King

(2) Establish a knight on b4, thus covering against Bd3

(3) Probably open the a-file as well after allowing ...a5/...a4/...a3, etc.

(4) Place QN in contact with d5, making ...d5 easier.

Aaaand??

Look, that's too much already, man, even if I can't remember #5.

Like Bobby said. A3 sucks for White in a Sicilian. He never wanted to play that.

White can try some cipher play on the Kingside to offset all this.

But notice that while Black's cipher play ended in a couple of moves (...b5/...b4), White's will go on...seemingly interminably:

f4 - g4...g5 - what's next? f5? - maybe h4? - what are you doing?

Are you attacking? Defending? Putting your house in order?

You're not even playing Chess, dog.

Now MAYBE you can play the kamikazee sac of g6!! with no support at all, if all your pieces are prepared for that, but that's only because Tal showed you that.

You would have never come up with that on your own, dog.

10 0-0-0?! d5!
11 e5 Nd7
12 f4 f6! (forgot to add these moves; sorry)

13 Qh5? fe!