What is a check-raise?
A check-raise (C/R) is when you check out of position (OOP) and raise after the player in position bets. You can only check-raise when you are playing OOP.
When you check in position (IP), you will just see the next community-card, and hence a check-raise is not possible.
Rightly used, the check-raise is a sneaky weapon. If you aim to play game theoretical-optimal Poker, you must check-raise with good frequency’s.

Why you need to check-raise
A poker player that doesn’t check-raise can easily be out-played. If your opponent doesn’t check-raise, or too few hands of his range, you could exploit him, for example, by betting for free-showdown with mediocre hands that couldn’t stand a check-raise.
These mediocre hands, you would have to check against someone that check-raises a decent amount as your holding is to weak to call his check-raise. Also, the player not check-raising enough will have difficulties, realising his equity with weak-ish holdings such as straight-draws that have no showdown-value, and get value with his very strong hands.
How do I justify a check-raise on the flop? What hands should I pick?
The best hands to check-raise on the flop are hands that are very strong and don’t fear any turns, and hands that aren’t strong enough (weak draws with back-doors but no show-down value) that could improve on later streets (turn/river), with a decently high likeliness.
You should check-raise with a semi-polarised range (strong and weak-ish hands). The aim of a check-raise is always, to either to get value with your strong hand or to get your opponent fold a better hand. Sometimes though, it is better for the sake of protecting your range, to not check-raise at all.
In some spots you just can't justify a check-raise
Before you are thinking about check-raising, you should always be wary of whether the card or board favours your range, or your opponent's. In general, you should only check-raise when either, your range allows doing so on the flop ( low-card flops, paired flops, wet flops), or if the turn/river has brought a card that was likely to have improved your hand. You never want to check a flop like this: A-A-2, and then raise your opponents c-bet. On flops that benefit your opponents range, you need to either call or fold with your whole range.
Check-raising mastery | Let's analyse/study different flops
First, we need to construct a hypotethical spot. Let’s say you play in the big blind, the button raises to 2 big blinds, and you call. You play for 50 big blinds at a blind-level of 10/20 (1000 chips) effectively, and the pot on the flop is 90 chips. As always, we are using the poker-tool – Piosolver to approximate game-theoretical-optimal strategies.
The pre-flop-ranges
Let’s peak at the flop!

7d-7s-3h
That is a very dry flop, and your opponent has a range-advantage given that the board doesnt allow many hits. You should never donk-bet this flop consequently.
In the image below, you will see what your opponent is supposed to c-bet on the flop when he wants to stay unexploitable.
Green-marked hands are suggested checks, and red -marked hands are suggest c-bets.
We notice that Piosolver suggests the opponent to c-bet with 40% of his range and that mostly with a very small size of 20% of the pot.
In the image below, we can see how we are supposed to act vs the opponents continuation-bet.
Green-marked hands are suggested calls vs the c-bet, red -marked hands are suggested check-raises and blue-marked hands are suggested folds.
We notice that Piosolver suggests to check-raise with a whooping 27%-range. That is a lot if you ask me, and hugely differs from how people actually play Poker.
On a paired board like 7-7-3 rainbow, we should check-raise for value on the flop with hands that are very strong (7x, full-houses), some hands that are likely to be ahead but will be in trouble on later streets (T3, J3, A3 etc).
You should check-raise as a bluff when you have some equity (54o 8d9s. 64 etc) that could pick up more equity on later streets. The reason why you would want to check-raise weak draws and some hands that have back-doors (back-door flush for example) is that you have a better chance of winning the pot playing them aggressively. If you check-call those weak hands, very often you will have to give up the pot and fold at some point.
Exploiting population tendencies
Now we know what hands to check-raise against players that c-bet with GTO-ish frequencies and sizes (small) on low-paired flops, but what if the opponent c-bets nearly every hand on such flops, and that with a big size?
How do we exploit that? Well, your opponent makes himself very vulnerable towards check-raises then, and I think that most players are very exploitable in those spots.
We should adjust accordingly and check-raise more 7x and 3x hands, and also check and then raise with most, if not all of our backdoors. We can also mix in some pure non-equity bluffs ala T9o, T8o, Q9o etc. You should preferably block hands that can float your check-raise, for example, Qd9s that blocks some QdJd, or Ts9s that could float you reasonably.
How do I proceed on the turn?
We want to move on with continuing betting on blank runouts (K, T, J or 9 etc.) with most of our range, and this with mixed sizings.
We benefit from having a small size for light value-bets and semi-good to good draws. A small continuation-bet on the turn will look extremely strong (as if you want to suck your opponent in), and this allows you to continue bluffing, even with small sizes.
You should continue betting the turn with small sizes with value-hands that block most of your opponents potential value-hands to suck him in (77 or 73s for example. What can he hold? He will fold if you bet big.
If you improve your hand and make a pair with T9 for example, you should c-bet the turn with a 35% size to get some light value, not always, but sometimes. Mix it up!
On the other hand, you should bet big with hands that are valuable but vulnerable, and with pure non-equity hands that benefit hugely from your opponents fold.
Polarise your range more when betting big.
Same spot, different flop
The circumstances of the next hand we are going to analyse/study are going to be the same. 50bb deep, the bu open-raises and we call his raise. Same pre-flop ranges.
Let’s peak at another flop!

Qh-Ts-8s
This flop differs much from the flop we have analysed/studied before. It is “wet”, and you will get a lot more action when you check-raise.
⇓ Again, you will see what your opponent is supposed to c-bet when he wants to stay unexploitable. ⇓
We can see that Piosolver wants the opponent to c-bet with a very wide range, and with a few different sizings. That is because our opponent has a huge range-advantage, and we have lots of hands that will might not be in trouble on the flop but on the turn or river when we are facing (big) bets. Our opponent has much more strong hands than us.
⇓ As you can see, you should rarely check-raise wet high-card flops ⇓
Why though?
Mainly because if you check-raise on a wet flop with your strongest hands, your range will become so weak when just calling that you barely ever see a river, especially if your opponent knows that you do the mistake and check-raise too often with your nutty hands.
Your range is capped on the Qh-Ts-8s flop already, and when you further kick out strong hands of your already capped range you are going to be in big trouble with all your pair, mid-pairs and so on. We don’t havy any sets besides maybe 50% of our pocket-eights, and maybe 30-50% of our J9s combinations given that we 3bet 88, J9s pre sometimes.
Our range consists of a lot of hands that have difficulties getting to the river when the opponent applys pressure by betting. He can put us on a lot of pressure on later streets, and even more if we start check-raising our strongest hands here (J9 mostly). You rarely want to mess around and check-raise this flop with a gutshot + back-door flushdraw or similarily weak hands.
In this scenario you are best off calling or folding with most of your range.
Let's analyse one more flop
One last flop we are going to analyse quickly. The spot hasn’t changed with the exception that a different flop is dealt.
Another flop!

Kh-Kd-7s
What do you think? Check-raising this flop a lot makes sense or better play a call or fold strategy? We don’t have too much of a range-disadvantage here as we hold many more Kx hands than the button. That might imply if you should check-raise this flop..
⇓ This is what our opponent is c-betting on the flop if he plays GTO. ⇓
Wupa! He can bet almost everything! As we have so many hands in our range we can’t draw to anything with on that flop, our opponent can continuation-bet almost any2 with a very low size of 20% of the pot. We are just forced to fold lots of our hands, even against his small 20% pot-size bet.
⇓ We can actually check-raise a decent amount here. ⇓

Why? There are several reasons why we can check-raise “so many” hands here (20%). First, he is c-betting all his weak hands that he partly needs to fold vs our raise.
And secondly, because he does not have a range-advantage. We have way more Kx combinations than he does, and hence our check-raise with bluffs are legitimised given that we have so many “value-hands”.
One this flop, we should, again, mostly c-bet with super strong hands (good Kx , sets etc.) and hands that have back-door equity. Hands like 8h-6d or 86 and 65 of hearts or diamonds are great bluff check-raises as they can make back-door flushes and straights. Don’t underestimate the value of back-door equity!
You shouldn’t value check-raise too light as you can see.
Don’t make the mistake to check-raise all your Kx hands; you need a lot of them in your check/call-range. Also, you block many hands that can call you when check-raising weak three-of-a-kind here. These hands aren’t valuable enough to go for three streets of value!
Last flop, i promise!
We have covered most type of flops but have one missing. The low-card wet flop! Let us analyse this flop together!
Last flop we analyse!

8h-6h-5s
⇓ This is what our opponent is c-betting on the flop if he plays GTO. ⇓

What do you suspect this time? Check-raise some or not at all? Let’s see.
⇓ We can only check-raise 11% on a low wet flop ⇓

What did we learn?
The more nut-hands are already possible on the flop, the less you want to check-raise (7-6-4, T-9-J E.g).
If the flop allows many draws but not too many made-hands, that invites for higher check-raise frequencies.
Don’t check-raise on the flop when your opponent has a range-advantage ( A-A-x, 2-2-3 etc.).
Low-paired flops are great for you to put your opponent under pressure with a check-raise.
Legitimise your check-raise bluffs with having back-door equity. You should rarely C/R non-equity hands.
Below, nono, don’t worry. I won’t show any more images of different ranges that will put you into oblivion.
Below, you can see a facial expression that you put on your opponents face when check-raising!