Roberts vs Casey (2) 9-16

moves 9 -10  

Black is an interesting move. It helps a potential Invasion at a and ensures a firmer grip on the right side.

However, I would not play it, because Black already has good invasion point at b (or c), to prevent white from getting easy point here, and it seems to be a little loose in combination with . Maybe x would be the right shape point here, but I am not sure. Well, in any case, is not completely off the mark.

seems to be fine too, strengthening . White might later answer an invasion at a with c, enclosing the corner, if the upper left group is alive.