Bluffing has nothing to do with what you have. You could be bluffing with 7-2 offsuit or pocket aces. Its all about what your opponent has, and more importantly what he doesnt have, given the texure of the board, the betting sequence, and the stack sizes. Nobody in poker is better at putting all these factors together to make a huge play at the right time than Phil Ivey. This is why he is the best.