Post Flop Betting Theory

Before we get into any specifics about how to play certain situations after the flop in no limit hold’em, we have to first talk a little general betting theory.  Here is the most important thing about betting post flop:  All bets must have a purpose.  Just as your life should be purposeful so should your bets.  Now, I realize that may same stupidly obvious.  But be honest with yourself for a moment.  I want you to really think about your post flop betting and tell me truthfully if you can clearly and convincingly tell me the purpose of most of the bets you make.  You would be surprised, most people can’t.  In fact, not betting with purpose is the number one reason people move in too much after the flop.  They don’t want to think, or they aren’t advanced enough to come up with, the appropriate bet for the situation so they just move all in, abdicating responsibility for the choice and risking their whole stack for no good strategic or mathematical reason.  If all I do is stop one of you from doing this, I will have done my job. And that is not to say that you should never move all in, you should, when it is appropriate and serves the purpose the all-in was meant for (we will be talking a lot of all-in in later articles in this series).
All right then, so let’s start at the most basic level which is to think through, before you ever make a bet post flop, what you are trying to accomplish in the hand.  Generally, there are only two things you are trying to accomplish with a bet.  The first would be that you want your opponent to fold.  The second is that you want your opponent to call.  Now sometimes you aren’t sure which you want, a call or a fold, at which point you want to design a bet for information.  Other times, and this comes up rarely, you don’t care if your opponent calls or if they fold, both results are fine with you. 
Now, if you are trying to get your opponent to fold, usually because you have a bad hand and want to pick the pot up right there, the average poker player will make a big bet so they look scary to their opponents.  In fact, this is where a lot of bad all-ins occur.  Making a big bet is generally never the right choice here.  Our purpose is to cause our opponent to fold by making a bet that will make him think we have a good hand.  But we also don’t have anything ourselves so getting called is a disaster.  The bet needs to purposefully balance these two facts, we want our opponent to fold so our bet needs to be big enough to represent an actual hand to our opponent but at the same time we want to control our risk in case we are wrong and get called.  What this means is that when you are bluffing after the flop you want to bet the smallest amount that will still accomplish your goal of getting your opponent to fold. This is the basic concept of stack control.  Bet the smallest amount that will cause your opponent to behave the way you want them to so that you are managing your risk well.  In fact, if you have ever wondered what Phil Hellmuth does that is so darn right this is it, right here.  He is a master of stack control betting.
Now on the flip side, when you want your opponent to call, you want to bet the largest amount that you think they will call.  Interestingly enough, the amount you come up with for a situation where you want a call is often the same as the amount you come up with for the situation where you want a fold, which brings up a point which I will hammer home throughout this whole series: You should never purposely mix up your play in no limit hold’em.  Whenever you choose to mix it up, you are choosing a lower equity line of play in order to confuse your opponents and pick up some equity later.  If you play properly, and bet purposefully all the time, you will never need to make a second best choice in order to mix it up.  Because the conceptual reason for making a particular bet can be very different, depending on your hand, your play will appear mixed up to your opponents.  What you will see over and over again is that you often come up with the same answer for a bet size when you have a good hand and when you are bluffing.  This is confusing enough already to your opponents so you never need to stray from the correct bet to try to obfuscate your play.  There is no reason to ever take the worst choice just to confuse. The running theme through this series will be that confusion is built in to appropriate betting strategy.
Now in the case that you aren’t sure if you want a call or a fold, your bet should then be designed to get information.  Logically, we want to pay the least amount for the information so an informational bet should be large enough that your opponent’s reaction to it will be meaningful but small enough that we are paying the minimum for the information we need.  We want to risk the least to find out where our opponent’s hand is but we still have to bet enough that his reaction to the bet will be meaningful.  Notice, that an informational bet will often look just like a bluffing bet since we are wanting to bet on the small end of the spectrum here.  Likewise, a value bet might look just like the bluffing and informational bets if we think our opponent will only call a small amount.
So, what is the right amount?  Well, in general you want to be betting somewhere between half of the pot and all of the pot after the flop (excluding the river).  So, from now on I will be talking about small bets as half pot size bets, medium sized bets as ¾ pot sized bets and large bets as pot sized bets.  The reason you want to stay in this range has to do with math and game theory.
On the game theory side, if we bet below half the pot on the flop or the turn ( I will get to the river later in the series.  The river is the one place where an extra small bet makes sense sometimes) we are making two mistakes, one from a game theory standpoint and one from a mathematical standpoint.  From the game theory standpoint, we need our bets to have meaning to our opponents.  When we bet below half the pot, make these tiny little bets, the range of hands that our opponent is willing to call with becomes quite large. Opponents who might have folded a hand like bottom pair or a gutshot straight draw or two over cards to a larger bet will call to a super small bet.  The problem here is that bets should be gathering information about our opponent’s hand, certainly when we aren’t sure whether our hand is good but even if we are looking to get a call because we will be better at maximizing value from our hands on later streets if we know what kind of hand our opponent has.  When you make a tiny little bet, expanding the range of hands your opponent might be calling with, you are not effectively narrowing down the range of hands your opponent could be holding.  Making a larger bet, a bet that is at least half the pot, will narrow that range down more effectively because it will cause your opponent to be more selective in his calls.  This is a good thing.  In general, the line is half the pot.  By betting somewhere around half the pot, at least, your bet has enough meaning that your opponent’s call will have meaning and effectively narrow down his range of hands.
The second mistake in betting too small is a mathematical one.  Whenever you bet, you are setting a pricing situation for both yourself and your opponent.  Now, granted, the smaller the bet you make the better the price you set for yourself.  This is why when we are bluffing or we want to just get information or if we are semi bluffing we want to bet at the lower end of the range because we give ourselves a better mathematical price on the play.  But when we go too low the problem is that we offer our opponent too good of a price.  Let’s say you bet ¼ of the pot.  There is $1K in the pot and you bet $250.  When the decis
ion goes back to your opponent there is now $1250 in the pot for him to call $250.  He is getting 5 to 1, that is what you have offered him!  Now 5 to 1 is a pretty good price on most hands he could be calling with.  As an example, if you have top pair and he has bottom pair then he has 5 outs to win or a 20% chance with two cards to come.  That means your opponent is a 4 to 1 dog.  If you only bet ¼ of the pot here you just actually offered your opponent a good mathematical proposition and that is a disaster, you just allowed your opponent to do good math.  Now the bigger disaster is if your opponent would have called a larger bet, say ½ the pot or more, in this case.  With the same $1K pot if you bet ½ you are sending the pot $1500 back to him for him to call $500.  Now your same opponent is getting only 3 to 1 on that same 4 to 1 shot.  Now if your opponent wants to play, you have made him pay to suck out on you…you have forced him to do bad math.  The fact is that in general a half pot sized bet will offer bad math to most hands that are drawing against you, even flush draws and straight draws since they are generally only going to see one more card.  Any time you can make an opponent pay for his loose play you are in good shape.  You never want to offer an opponent a good price on a hand when that opponent would have happily taken a bad price. If you do and your opponent sucks out on you don’t come complaining to me because I will tell you it is your fault. You only get to complain about bad beats when your make your opponent do bad math.
Now, from a psychological standpoint, opponents generally react about the same to a half pot sized bet as a whole pot sized bet.  In fact, if anything, opponents will often read the half pot sized bet as stronger since it is still large enough to be meaningful to them but it looks more like you are inviting a call which is scarier to them.  Given that opponents will react the same to those two bets, why would you ever bet toward the whole pot if you are trying to get a fold or just get information.  If an opponent will fold just as often to the smaller bet as the larger one, the smaller bet will always be correct since you will be risking half as much money on the play.  Seems obvious and yet most opponents when they are bluffing tend to bet all or more than all of the pot size so they appear very scary to their opponents.  First, they are risking twice as much as necessary in order to get the fold.  Second, their bet is often screaming to their opponent that they don’t want a call.  Those bets are counterproductive in every way.
So on the bluffing side, choose the smallest bet for the table you are at and the opponent you are dealing with that you think will be believable and get your opponent to go away.  Sometimes that amount will be closer to the whole pot, depending on how your table is playing.  But you should always try to get away as cheap as possible.
On the wanting a call side, you still want to bet at least half the pot for the same pricing issues and informational issues.  If my opponent does call, I want to know what they have so I can extract maximum value from their hand on later streets.  Second, even if I am sure that I have the best hand my opponent will almost always have outs against me with two cards to come and I want to make sure I am making them pay to try to hit those outs.  I never want to give my opponent a good price to call with the worst hand against me when he will take a bad one, even if I am begging him for a call.  So on the calling side, choose the largest amount your opponent will call, which is often half the pot still…but if your opponent will call the whole pot, hey, more power to them.
Why should you never go above the whole pot?  Well that is simply because you never want to be laying a price on the pot if you can avoid it.  If you bet more than the whole pot you are now laying a price that your play will be successful.  Compare these two situations:  You are bluffing and you bet half the pot.  You are giving yourself 2 to 1 that your play will work which means that for the bluff to be profitable right then you only need to win the pot a little over 33% of the time.  Now that is a low pressure play.  You don’t half to be right that often that your opponent will fold in order to profit from the play.  Now, what if you are bluffing and you over bet the pot?  Let’s say there is $1K in the pot and you bet $1500.  Now you are laying 3 to 2 on the pot meaning in order to be profitable on the bluff you need to win over 60% of the time.  Which mathematical proposition do you want?  What is even worse is that opponents who have nothing and are going to fold anyway will usually fold for the half pot size bet as well as the over bet.  So you are putting unnecessary mathematical pressure on yourself, forcing a higher success rate on the bluff for no reason. So avoid over betting the pot (although, again, sometimes it is correct on the river only, which we will get to later in the series).
Now the last bit to cover in general betting theory has to do with preempts to the theory of staying within the ½ to full pot sized bet range.  In tournaments in particular, but sometimes in live games as well, stack size demands a different sized bet.  Your stack is only as big as either the chips you have or the chips your opponent has.  In the case where an appropriate bet is already somewhere around half the smallest stack, yours or your opponent’s, you should generally go ahead and bet the whole thing.  This is because either you are pot committed with the bet or your opponent is. If you are pot committed with  your bet (whether the bet is half the pot, ¾ of the pot or the whole pot) go ahead and shove all in, especially if you are not looking for a call anyway.  You can’t mathematically fold once you have bet over half your stack anyway if you have any outs so you might as well just put it all in and let your opponent know you are going to the river. The only time you might bet half your stack would be if you are really begging for a call but even in this case those half stack bets often raise suspicions in opponents and a full stack size bet is more likely to get a call.  This all holds true if it is your opponent’s stack that is small.  If the right bet is over half his stack, go ahead and put him all in, even if that means betting more than the pot.  Mathematically it doesn’t make much sense to do otherwise.
So, remember, stay between half the pot and the whole pot in your post flop bets.  The game theory and mathematical reasons for doing this are too compelling not too.  Next time, we will talk about how to play big made hands in and out of position on untextured boards.