4/8 limit hold 'em, yesterday. UTG has played passively. I was in the cutoff with Ac7c. UTG limps in pre-flop, 1 other player calls, I raise. Folds around to UTG, who calls. The other caller calls again.

Flop was Q73 with one club. UTG bets, gets 2 calls.

Turn is a jack of clubs. UTG bets. Other player folds. I raised. UTG calls my raise.

River was an ace of diamonds. UTG checks to me, I bet, and he calls. I show my hand, he mucks his.

What happened here? Well, almost assuredly, UTG had a pair of queens. I was trying to draw out on him. When that turn hit, I now had 14 outs out of 46 cards. (Indeed, even if he had 2 pair, I had 14 outs unless he had a 7.)

So instead of just calling, I want to raise this turn. Why? Well, let's look at the advantages:

1. We may be able to induce a fold from a stronger hand, if Villain puts us on 2 pair or a set.

2. If we hit one of our outs on the river, we will have built the pot and may win more money.

3. We have confused Villain about what we have and the strength of our hand. This is especially valuable if we hit our flush, but it has some value even if we just hit 2 pair. (Villain later told me he didn't know what the heck I had and that's why he took a risk and called on the river.) Plus, it might even set up a bluff on the river if we miss and we think the Villain may fold to a river bet.

4. We can get some information about Villain's hand-- if Villain re-raises or leads out on the river, we may learn that some of our outs are no good or Villain has a hand that we can't beat.

5. We may get a free showdown on the river if we miss and decide not to bluff-- this may allow us to collect a pot if it turns out that Villain was playing a marginal hand, bluffing, or c-betting.

In the games I play in, I see people check-calling their draws all the time. Their theory seems to be to stay in the hand as cheaply as possible, and then bet if they hit (or perhaps bluff if they miss). But the aggressive play is often better here.