4-4 point low approach high extension, slide diagonal three-space extension

44 Small Knight Approach  

The normal followup is for White to extend to a. Kogo claims this as an overplay that can be punished as follows:

Punishment  

After Black 11 at a, the Kogo variation indicates that the three white stones are lost and ends. That seems reasonable, they don't look very healthy.

However, I'm not quite sure I see the follow-up.

Possible Punishment Followup  

I tried in various spots, but in all the variations I tried, White wins the capturing race between the two. What am I missing?

Andre Engels: Could you be a bit more precise of what capturing race you mean? The diagram you are showing looks like a clear black win to me.

Icepick: It's amazing what a fresh look at a problem can do. There's a reason that I'm a DFK.