I thought of posting this one last night. In general, when someone limps in the small blind to your big blind, you should raise. I find that about 70% of the time they will fold pre-flop or on the flop, making the move profitable with any two cards. If someone routinely folds pre-flop when you do this, you probably should tread lightly when they check-raise the flop. They probably really caught a piece. If a generally aggressive opponent completes and then reraises when you raise, he usually has a big hand.
Categories