Bluff versus Monster- One of the largest (and most misused) weapons in a poker player's arsenal is the check raise in all of its variants; the check / shove, the check / click-raise, and the standard check / raise. Almost always, this bet is made to signify a monster hand that has been slowplayed until now, and has already been sprung upon its opponent as if to say, "Here's the real hand, you better have a monster to compete against me now." The beauty of this logic comes in making bluffs with the check-raise; instead of continuing betting a flop and saying, "I do this a lot, so I'm full of crap here a lot ..." you check, he fires with position, and you snap back over him with the check / raise, saying, "Oh, I checked to let you bet, now I'll show you where the real hand is at!" and take down a larger pot than usual with your unimproved Q8d on the flop.
To bluff or check raise bluff? - The check raise bluff has a few cons that go along with the perks of a more believable bluff and a bigger pot won when the bluff does work. When the bluff fails, you stand to lose substantially more chips than you would if you tried a standard bluff and it failed. Think about it; you open for 3x, try a CB for 4x, get raised, and fold; you lose 7 BB's. The check raise bluff, you open 3x, then check the flop, and make it 14x when your opponent leads 5x, and he goes all-in, you fold, and instead of losing 7 BB's, you lose 17! Only use the check raise bluff as a variant and against players who have shown respect to check raises in the past. This is also a bluff I highly discouraging showing down; the value it has as a bluffing tool will vanish if caught, and showing the bluff does little for your reputation, but gives the entire table a big look into what you're capable of on the flop; you want players to respect you and leave you alone, not get suspicious and attempt to figure you out.
The river check raise bluff- The variant of this that is the most boring (and most profitable, if used correctly) is the river check raise bluff. This requires a sound knowledge of your prey before you use it; he has to be known to pounce at weakness, and you have to have shown prior hands where you have checked down very strong hands; think third nut flushes or middle sets on dry boards, making it look like you were trying to trap. With usually a decent pot built already, you may think bluffing the river with your bricked brush draw is best; but the odds that straight bluff would work are usually poor. However, if you check, then raise your opponents river bet, on a board like Qh10c7h4d8s, how good does a hand like Q9 or JJ look at a board like that? This is an especially good tactic if your opponent has a history of making thin value bets when checked to on the river; he may actually be holding something like 109 or A7 and have absolutely no chance of calling your check raise. Remember though; when these fail, they're expensive failures. Use at your own risk!