Poker Strategy: Choosing our bet sizes preflop - 3-betting and 4-betting

In the first part, we discussed opening and isolating sizes. Now we'll see how position affects our sizing, including the somewhat unique blind versus blind situation. You'll see why it's crucial to be elastic with our sizings and why not to stick to static 3-bet and 4-bet sizes.

So, the next group of sizes we must discuss is when we face an open raise and have the opportunity to 3-bet. Again, we will rely on theoretically optimal sizes that solvers suggest. However, this doesn't mean you cannot differ from them. Only you need to understand the consequences and how size changes affect ranges.

First, we'll discuss in-position play, meaning someone opened from UTG to CO, and you sit in position (MP-BTN). Usually, we elect to 3-bet somewhere between 3-3,5x. So, please forget to stick to static sizes and try to adapt to the open size you face. This way, you can avoid investing unnecessarily considerable amounts or 3-bet too small, thus providing way too good odds to your opponent. For example, when MP opens for 2,5bb, you should aim for something like 7,5-8,5bb, but if she opens for 2bb, you are okay with a 6,5-7bb sizing.

Blind versus blind play is a bit unique even though you have a 3-bet opportunity from the BB in position; since the open sizes usually are bigger, the ranges are also wider. These circumstances lead to smaller 3-bets, usually in the 3x region. The most common is a 3bb open from SB and a 9-10bb 3-bet from the BB.

The out-of-position 3-bet sizes are typically larger than the in-position. The reasoning is very similar to the above-discussed isolation spots. Namely, you need bigger sizes to mitigate the positional disadvantage. If you 3-bet around 3x OOP, that provides tempting odds to the opener, and the EV of their hands goes up significantly. So when facing an open from the blinds, you should aim for a 4,5-5x size. When BTN opens 2,5bb, you might go for 11-13bb from the blinds, for example. Due to the range construction and positional differences, you could go bigger from the BB than from the SB when 3-betting. Maybe in practice, it's easier to stick to the same size from both blinds and adjust only based on other factors when possible.

A specific 3-bet situation is when a player opens and another cold calls that, then a third player has the opportunity to 3-bet. This is the so-called squeeze; the 3-bettor puts extra pressure on both of the players at the same time. We are in a territory with multiple changing factors, so the best advice is to consider all information. Positional awareness is essential, just as in any other spot. The best simplification you could use is to go with your standard 3-bet approach, multiplying the original bet by 3-5x, plus adding the cold-called amount to your 3-bet. If this sounds complicated, let's see two examples:

1. MP opens 2,2bb, and the CO calls. You sit on the BTN; normally, you would 3-bet around 7bb (3-3,5x in position). If you add the CO'sCO's cold call (2,2bb), you get the right amount for squeezing: 9-10bb.
2. CO opens 2,2bb, BTN cold calls, and we sit in the SB. Using the same method, you normally would 3-bet around 11bb (4,5-5x), but you need to add the amount of BTN put into the pot. So you get around 13bb as the right squeeze size.

We mentioned adjusting to other factors above. We should focus mainly on Villains' tendencies and exploit their inequalities. Especially in small stakes, players open suboptimal ranges or learn some preflop charts without fully understanding them. Anytime you see someone opening a wider range, using a bigger open size or folding extremely high frequency (65+, sometimes even 80%), you should adapt to them. The most common mistake is inelasticity in their ranges. While in theory, you must adapt sizes and ranges to changing opens, in reality, they don't alter their strategies when you size bigger or smaller; they are not aware of the configuration. The best way to exploit this is not to increase your 3-bet sizes if they are overfolding and raise them way bigger when they are overcalling. You'll get a great prize on your bluffs in the first case, and you make them pay extra (eventually committing a –EV play for them) when they are sticky.

When we talk about 4-bets, it's a tiny part of the game, but it's still vital to use reasonable sizes. Of course, position will play a key role in the sizing again, and it's very situation-dependent. It's not the same as facing a 3-bet from the CO against the BTN or facing a 3-bet from the BTN against SB or BB. Not to mention cold 4-bet spots, when a 3-bet occurs, and a third player reraises, who hasn't been involved in the action yet.

Typically, we 4-bet smaller in position and larger out of position in terms of multiplying the original 3-bet. Because OOP 3-bets are naturally bigger, we don't want to, nor do we need to commit ourselves to the pot. Moreover, we'll have a positional advantage and better EQ realizability. Usually, we go around 2,2x IP, for example, opening BTN for 2,5bb, SB 3-bets to 11bb, and we choose to 4-bet to 24bb.

OOP, we'll be more likely to be around the 3x region of 4-bet sizes. For instance, when we open the CO for 2,2bb and get 3-betted by BTN for 7,5bb, we should choose between 21-23bb. The blind versus blind play is a bit unique again. A lot depends on the 3-bet size, but in theory, you should go somewhere between 2,2-2,5x. Nowadays, it's common to see regulars go bigger, up to 25-27bb. You should test your opponents, and if they are not sensitive to size changes, you'll elevate your EV by 4-betting the suggested smaller sizes.

The numbers are very similar in a cold 4-bet spot, probably around the lower end since the ranges get very narrow. You won't commit any big mistake using the 2,2x IP and 3x OOP sizing.

As you can see, the 4-bet sizes are very similar when you look at the numbers. They range between 20-25bb depending on the position. Still, it's better to remember the multiplier to be able to respond in a theoretically optimal way instead of sticking to a certain number. Imagine that UTG opens 2bb, CO 3-bets 6,5bb, and you are on the BTN. Why would you risk 20-22bb to 4-bet? One of the consequences is that you limit the width of the range you can apply for such a vast size. Another is that your opponents will be more incentivized to push all-in immediately. Therefore, a 15-16bb will work more than just fine. You might ask, doesn't the top of my range want to invest as much money as possible? Well, partly, yes. But let me ask you, doesn't the top of your range want to keep relatively low EQ hands in play, too, that will have to make multiple streets of marginal decisions?

Hopefully, now it's clear that you need to distinguish in-position, out-of-position and blind versus blind spots as we provide different EVs if we raise too small and risk unnecessarily considerable amounts when we raise too big. In 3-bet pots, in position, we'll choose smaller sizes, somewhere between 3-3,5x raises and out of position, we usually elect larger raises, around 4,5-5x. In 4-bet pots, the pot is already so big that it is counterproductive to go for a huge sizing. Therefore, our 4-bets will work around 2,2-3x, depending on positions and situations.

Next time, we will discuss unconventional spots, such as exploits and adjustments to various stack depths.