Unexpected Move

I am really enjoying my more frequent playing and I get lots of opportunities to learn new things. Too bad I hadn't read Go Game's Guru article 5 Tips for Dealing with Unexpected Moves yet when I played this game. My opponent surprised me by playing A in reply to my pincer.

 

Even although I did stay calm (tip 1) I did not particularly respect my opponent ('This must be a mistake or a misclick or just no clue what he is doing'). I didn't really take my time to figure out his plan or read out everything. I just started playing in reply and hoping for the best. At first it seemed to be ok.

 

Until it wasn't ok anymore. Oops. This was a very bad not good result at all.

 

By now I have done some preliminary research and Kogo's says that this indeed is an existing move (who wouldave thunk!?) 'A special strategy, if White has something like the High Chinese Fuseki on the lower side..'

I also found the move in some pro games but haven't really figured out yet what to do next time. I guess it should be on my 'moves to study' list.

The game can be found here.