Traditionally, when people think of bluffing, they think about making a large, intimidating bet that blusters an opponent out of the pot. But a more effective and cost-efficient bluff is one in which the size of the bluff is based on what your opponent thinks of you and also on the strength of his probable hands. Sometimes a very small bluff can be the best option, for surprising reasons.

Earlier this month, I played in the World Poker Tour's $10,000 Five Diamond World Poker Classic at the Bellagio in Las Vegas. On Day Three, we were about 10 players away from the money, and I was fortunate to have landed at a soft table. However, I was fairly card-dead, and we weren't close enough to the bubble that it affected people's decision-making, so for quite some time I just folded.

Finally, in a hand that occurred just before we headed to break, I took a shot at someone pre-flop. Action folded to a player in late position who raised, and I three-bet him one off the button with 5s 3s. Naturally, I was hoping he'd just fold, but when it folded back to him, he made the call.

The flop came Qc 10h 6d, and my opponent checked. I thought the flop had a texture that connected pretty well to the kinds of hands this particular player would call a re-raise with out of position, so I decided to check back and fold the turn if he bet.

The turn brought the 4d, and I picked up an open-ended straight draw. When my opponent checked, I bet slightly larger than I had made it pre-flop -- a bet of 4,500. My opponent called.

The river brought a useless 4s, and my opponent checked. That was definitely an unfortunate card, and it made a larger bet a very bad idea, because he would probably call with stronger pairs like queens and tens. However, there was another part of his range that probably wouldn't call a small bet: all those missed draws that would still give him the best hand simply because my hand is so weak.

This particular opponent was a little passive, so it was possible he was holding a hand such as J-9, K-J, A-J, 7-5 suited or two diamonds -- the sort of hand that would lead him to check the turn instead of betting. I had absolutely no showdown value and could only win by betting. I also felt that a small bet would appear to be a value bet and would get him to fold anything that wasn't a pair. I bet 6,500.

This confounded my opponent. He shuffled chips back and forth, taking them from atop his pile, shuffling them and counting them out, then putting them back on top of his pile and staring at me. "Why couldn't you have bet more?" he said. "Ah, jeez, it's so clearly a value bet."

I remained quiet. Finally, he took the necessary chips off his stack and dropped them reluctantly in the pot.

"You win," I said. He tabled his pocket eights, and I tapped the table, then tossed my hand toward the muck.

"I wish you had bet bigger!" he said as he began stacking the chips. "I'd have called you so fast!"

Tony Dunst is a poker pro and host of "Raw Deal" on World Poker Tour telecasts.