Sometimes we need to make moves that allow free access to our opponents, but we should avoid it when possible - here's a case where it is possible.
The Blue T is problematic because it leaves Green immediate, free access to the higher part of the board.
Blue had a chance to play a different move to block Green while accomplishing exactly the same things (i.e. have the same active corners, have the same blocks on other Green corners, still be a 5-piece).
NOTE: if Green DOES play his i1 to advance upward ... notice
that the T4-leak mentioned on an earlier page
is sitting right there for him to use!
