Detecting a bluff in poker

Note: Not at the old Poker1 site. A version of this entry was originally published (2007) in Bluff magazine.

In some poker circles, I’m best known for my work with the body language of poker, usually known as tells. Mike Caro’s Book of Tells will celebrate its silver anniversary in 2009. That’s twenty-five years! Parade permits for London, New York, Boston, Los Angeles, and Tulsa are nearing the final stages of being processed, pending receipt of applications.

I kind of got pigeonholed when that book was published. I became better known for tells than anything else. And that annoys me, because, actually, most of my research has dealt with statistics and strategy, often backed by my own computer analysis. To put it simply, I’m a cross between a nerd and a geek who has been misconstrued to be a people-observing, prescient, kind-hearted guru. Oh, how that hurts!

Universal tendencies

Don’t misread me — I’m proud of my book, and those tells have stood the test of time. You don’t hear many people arguing with words like “Caro was wrong. A player isn’t holding a strong hand when he does that; he’s bluffing.” And there’s a reason you don’t hear such quibbling. All those tells came from deep within me and deep within other players. When you learn about these tells, you instantly realize that, hey, they really are universal tendencies — players really do act that way to disguise their hands, because you tend to do that yourself!

Today, I’m going to talk about bluffing. Specifically, I’m going to talk about how to know when an opponent is bluffing through use of tells. Here are some major things you need to know:

Keys to bluffing

  1. Bluffers are afraid to trigger your calling reflex. I’ve previously shared the secrets surrounding the “calling reflex.” The concept is that nobody comes to a poker room hoping to throw away hands. Instead, players gather at the table hoping to play hands and make calls. This bias toward calling, rather than folding, means that players are more suspicious than they should be. Any erratic movement or speech coming from the bettor is apt to trigger their calling reflex or, at least, to make a call more likely. Now, here’s the deal. You and I understand that intellectually. But others understand it unconsciously. Years of poker warfare have made them vaguely aware that their actions can cause suspicion in opponents. That’s why most bluffers refrain from taking actions that might cause suspicion and trigger calls.
  2. In fact, sometimes bluffers barely breathe. On rare occasions, they don’t breathe at all. I carefully observe opponents breathing when they bet. Often bluffers tend to take unusually shallow breaths. They’re afraid that loud breathing will lead to suspicion and a resulting call. So they over compensate. Watch carefully to see how an opponent breaths under normal circumstances. If that player’s breathing is significantly less pronounced following a bet, there’s a good chance you’re up against a weak hand or a bluff. This advice is especially valuable on final-round bets in limit games and anytime a large wager is made in no-limit games.
  3. Bluffers are unusually still. You should always note how animated an opponent is after betting. There is often an obvious decrease in movement if an opponent is bluffing. Players who have wagered on strong hands are typically more relaxed and their movements appear natural. Bluffers are more rigid and restrained. Often they freeze. They try to appear invisible, fearing that the slightest motion will trigger your call. Think of a person hiking through the mountains and encountering a rattle snake. If they’re smart, they’ll freeze, wanting to do nothing that will encourage a strike. That’s how bluffers act. If bluffers move at all, it’s usually at the last moment in desperation when a call seems almost inevitable. But, even at that final, fateful moment, most tend to remain still.
  4. Bluffers can’t carry on sensible conversations. If you’re not certain if your opponent is bluffing, try to initiate a chat. Those with significant hands are able to talk normally, and what they say makes sense. Bluffers will often sound stilted, instead. Their words — if they talk at all — will seem unfocused and unnatural.
  5. Bluffers may look back at their cards when you begin to call. If you’re still not sure whether your opponent is bluffing, fake a call. Reach menacingly toward your chips. As a sign of panic, bluffers may look back at their cards, trying to convince you that they hold something monumental. This is a dead giveaway. Players who really do hold strong hands won’t take any action at that key instant to stop you from completing the desired call. They’ll simply stay still and let it happen.
  6. Bluffers don’t show any change in mood whether you appear to be calling or raising. Here’s an advanced ploy I sometimes use to elicit clues about whether an opponent is bluffing. First, I’ll count out enough chips to call. Then, after a dramatic pause, I’ll add to the call amount, suggesting I’m planning to raise, instead. Players who hold strong hands often will react differently. A call and a raise are dissimilar to a player betting from legitimate strength. A call may be desired and a raise worrisome. So, if I see a change in reaction, it’s more likely that the bettor has genuine strength. But bluffers don’t care. A raise and a call spell the same doom, so their reaction is unlikely to change. If I see no modification in response, I give more credence to the conclusion that the opponent is bluffing.

Anyway, I hope that helps. Gotta go, phone’s ringing. — MC

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Mike Caro

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Known as the “Mad Genius of Poker,” Mike Caro is generally regarded as today's foremost authority on poker strategy, psychology, and statistics. He is the founder of Mike Caro University of Poker, Gaming, and Life Strategy (MCU). See full bio → HERE.


19 thoughts on “Detecting a bluff in poker”

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  1. Hello Mike, my longtime friend! I cannot even begin to say how much money this one Tell of yours has made me. It’s after the player bets, they stare motionless at the pot. I use that Tell at least once a day to make a call I wouldn’t otherwise make. If they haven’t read your book, it is the natural thing to do. Endless gratitude to you my friend for that tip. Now please stop educating people. (:

  2. Could counting your chips out like that these days be considered angle shooting?

    1. Hi, Jason —

      I’ve never heard of arranging your chips in front of you being considered angle shooting, unless you actually make a betting motion.

      — Mike Caro

  3. “…and women players are harder to read.”

    Any man who could ever truly read a woman would only need to be a recreational player anyway because his millions would be made over night writing relationship-help books.

    1. Woman are easy to read. Understanding them is impossible.
      On the serious side, Mike's principles apply equally to men and woman.

  4. If the Book of Tells is 25 years old, we aren’t the only ones who read it! A lot of savvy players give false tells, or just stay perfectly still no matter what they are doing to avoid giving off tells. I’ve seen so many people do exactly what Mike says in poker rooms, sometimes it’s hard to not laugh out loud, it’s like watching his videos. But, good players, esp good older players, I assume they are not going to be giving off classic tells. Pretty sure I’d be doing felony time, if stealing money giving off false tells was illegal.

    Since I am sure not the smartest player in the poker room, I have to figure some others they do that too, and then figure out the players individually. I, myself, am a seething cauldron of tells and doubt my ability to ever stay still or quiet for long, so I adopted a lot of quirky talk and false tells to cover that up. I also think poor male players are more transparent against female opponents, in general, and women players are harder to read.

  5. Mike,

    The opposite is also true. I became “animated” to fake wanting a my opponent to bet. In reality I really wanted my opponent to check thereby solidifying weakness.

    I was in a game this past weekend in AC and a scare card came on the river. The player started to show some doubt as to whether or not I made the flush. As I saw him be more and more reluctant to bet I started to look at the other players who were bouncing their gazes between the other player and myself trying to figure out the situation. I started subtly signaling to the other players at the table that I was going to win. This must have been communicated back to my opponent and he decided to check. I shoved all in and he folded. I had rags.

  6. Point # 6
    So how do you catch the moment of “changed reaction” if you are busy with the chips counted out for raise? I’d like to see this one on video!

    1. I don’t think the point is to prepare a bet; rather to _appear_ to prepare a bet. Pull a stack chips away from “storage” and into “preparation area”, and start stacking them in 5s. He’ll get the idea.

  7. Points # 3 & 5
    So a bluffer can be induced to MOVE…a beginner bluffer perhaps. However when he is good, he’ll remain still, yes? But how good is he if he remains motionless? That is also a testimony for bluffing. I see a contradiction here, a room for misread! Of course the reference Mike makes is over the course of the time line from the bluff made to the completion of my action. So we have a dynamics to this situation, therefore I’d like to see more details how to best analyze a bluff.

  8. Regarding point #2
    I vividly recall a bubble moment in MTT @ my local card room where I was a mid size stack player going up against a HOT running player on my left with my QJ when Q came on the flop. My initial pre-flop raise was called, my continuation bet was followed by his all in. My decision was: Going for first place and risk going out on bubble or play it safe and lay it down even at a steep price of losing 60% of my stack? I looked at him carefully for signs about the strength of his hand.

    He was leaning forward, his eyeballs were bulging out like a chameleon and he was motionless. He was not breathing! I made a call taking him for a bluff. He had AQ and I went out on the bubble. Where did I go wrong with my reading of him?

    1. Not sure, Zsolt. I would have had to be there to see the action in context.

      It’s important to understand that most tells aren’t 100 percent accurate. You should use them as additional information to be weighed along with other factors in making a decision.

      The leaning forward part could be an attempt to lure you into calling. Remember, opponents who are bluffing want to remain inconspicuous. They tend to strive for invisibility.

      The fact that your opponent wasn’t breathing IS usually a strong indication of a bluff, but the other mannerisms might have run contrary to that assumption.

      Straight Flushes,
      Mike Caro

    2. I’d say you forgot the first half of Caro’s Fundamental Law of Tells. You have to first decide if the player is acting. This one apparently wasn’t.

  9. Awesome article!! I know it will help make me a lot of money with the people I play with.

  10. Mike Caro where have you been? I thought you dropped off the end of the earth. Good to see you are back out here writing neat articles.
    How is Orac anyway?

    1. Hi, Narmac —

      I’ve become a hermit in the Ozarks, if that’s what you mean. Haven’t stopped writing (still have featured columns in two magazines and new books on the way), lecturing, or playing poker.

      Orac is feeling fine, thanks. (For anyone who doesn’t know, Orac is my artificially intelligent computer player — Caro spelled backwards.)

      Thanks for making your first comment and joining our Poker1 family.

      Straight Flushes,
      Mike Caro

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