The flop is hold'em's defining moment. For the cost of one small bet, you get to see 71 percent of your cards on the flop. That's right; the flop comprises five-sevenths of your entire hand. It's one of poker's biggest bargains. Because of that, it's imperative that the flop fit your hand in order to warrant the relatively pricy decisions to see the turn and the river. Deciding to see the turn or the river means seeing fewer cards at a higher price, and you need to have something that makes your investment worthwhile before making this decision.

Fit or fold - a phrase coined by poker author Shane Smith - means a couple of things. The first example is obvious: The flop should help your hand. If you begin with Q-J and the flop is Q-J-3 you've made two pair and were obviously helped by the flop. In fact, you can say it fit your hand like a glove. If you began with a weak hand such as 4-4 in the big blind and flopped a set of fours, the flop smiled on you in an even bigger way.

But that's not the only way the flop can fit your hand. If you started with 9-8 and the flop was T-7-3 you flopped four to a straight and will probably get the right price from the pot to justify playing on in hopes of making a straight. The same holds true if you began with two suited cards and were fortunate enough to find two more cards of your suit on the flop. Now you have a four flush and that's usually a draw worth playing too.

In addition to a flop that fits by pairing your hand or providing a draw to a big hand, the flop can help you by not assisting your opponents at all. Suppose you raise with a pair of queens before the flop. You're rooting for a third queen on the flop, but there are a lot of cards you're rooting against too.

Even though you were the raiser before the flop, you'd like to dodge a king or an ace, because those cards can give an opponent a pair higher than your queens. You'd also like to duck two or three mid-range or big adjacent cards because they increase the possibility of someone making two pair, a straight draw, or what's worse, a straight. If the cards are two-suited you have to fear a flush draw, and if they are all one suit another player might already have a flush.

But if the flop is J-7-3 of mixed suites it effectively fits your hand because it probably missed your opponents' hands. Unless someone has flopped a set - and the odds are against that -your hand, which was almost surely the best one before the flop, is probably still in the lead with only two cards to come.

You're in good shape at this point. You can bet and force any opponent with a lesser hand to take the worst of it if he or she decides to call. With the best hand, betting gets more money into the pot, and that's a good thing too. You are building a pot you are favored to win, while making it more costly for any opponent to stick around in hopes of outdrawing you. When you're playing Texas hold'em, here are three rules of thumb for playing the flop:

• Play if the flop improves your hand right now.
• Play if the flop provides a draw to a straight or a flush that figures to win the pot if you complete it.
• Play if you have the best hand before the flop and the flop is so ragged in texture that it figures to miss your opponents' hands as well as your own.

If none of these conditions are present, you can consider the flop to have missed your hand, and you have no reason to be in the pot unless you have a valid reason to believe your opponent is likely to fold to a bluff. But that's a different story for a different day.