Bill: Next, is big, cutting off and capturing the stones.
However, Black has counterplay (next diagram).
Bill: Black attacks the stone, which was played to allow White's earlier cut.
- captures and , but they are chickenfeed at this point in the game. W b may be better, even though Black has play against White's center stones, thanks to .
Bill: After I would feel nervous as White. Black's wall has weaknesses, but they seem difficult to exploit, now. White, however, seems oblivious to any danger.
threatens to invade Black's huge moyo, but invites , which makes a successful invasion very difficult, if not impossible. Maybe White has to try something right away, instead. a through d come to mind.
allows , which can easily make a base. e or f instead is much better. After White has little chance to win this game, IMO.