The fundamental strong draw is the nut flush draw. This is the "Generation M" draw - M for Ed Miller, author of Small Stakes Hold 'em - where people seem to go overboard and bet, raise, 3-bet and even cap the betting with any flush draw. It's true that raising with a draw on the flop is a powerful move, and most definitely +EV in the right circumstances, but not always and it's definitely not always what gives the highest expectation, even when it's positive.
The idea behind raising a flush draw on the flop is one that is rooted in equity. Because flush draws hit so often - about a third of the time when there are two cards to come - and because flushes almost always win, it's usually safe to think of a flush draw on the flop as 33% to win. If you have two or more opponents in the pot with you, any bet that is made will be matched with at least two more bets so therefore you're at the very least neutral about putting in any amount of money on the flop. Did that make sense? Let me rephrase.
Ignore the cards for now, and just focus on the pot. The pot is a pile of money, and when you say that you have 33% equity, what you mean is that when all is said and done, you get to keep one third of the money in that pile. So in order to make money, you just need to put in less than one third of the pile to come out ahead; if the share that you put in is less than the share that you take out, you win money. Isn't that obvious? You know that the share that you take out is 33% - because that's what your chance of winning is - so all you need to do is make sure that the share you put in is less than 33% and you're solid. Since everyone puts in as much in hold 'em (barring the event where someone goes all-in) you know that if you have two opponents you will put in a third of the money, and you will essentially be break-even on the flop, as far as betting and raising goes. And if you have more than two opponents, you should be happy to put in any amount of money because your share to take out is still one third, but your share to put in shrinks for every player that's in the pot with you; with one opponent you're putting in 50%, with two opponents you put in 33%, with three you put in 25%, etc.
Now back to the cards. Our conclusion is that with a flush draw on the flop, you should be happy to put in lots of money with a flush draw when you have three or more opponents, and at least neutral about putting in money with two opponents.
But there are so many of the players at my tables who will not only bet and raise with a flush draw, but also 3-bet and cap when it's just them and me! So if they need to hit their flush draw to win, they're putting in half the money but will only take out 33% of it. Why are they raising? I'm certain it is because they read somewhere that it's +EV. But what's worse is that they do this betting and raising only with (strong) draws. It's extremely predictable with some players: They slow play monsters (sets, etc.), they bet/call or raise with decent hands, and they bet/raise/re-raise/cap only with draws. I'm not sure if they realize how transparent that makes them. Let me put it like this: If I'm holding AK on a K-7-2 board, two hearts, and my opponent who fits the above pattern caps the betting, he may as well play the rest of the hand with his cards face-up. And that's bad for him because he won't get paid off when he hits his flush, and I'm going to force him to put in as much money as I can on the turn as well.
But it doesn't have to be that extreme for it to be a less than optimum move. Let's say that you're playing with two opponents who are decent but don't know you at all. You're on the button. One player limps, and you raise with AJ of spades. The tight big blind makes it three bets, and you and the limper call. The flop comes K-8-5, two spades, and the big blind leads out, the limper calls and you...
... raise? It's doable. Given that you have the nut flush draw, you're probably at worst break even when you raise here since it's likely that both your opponents will call when the action gets back to them. But it's only "likely," not certain. Two bad things can happen:
Sometimes people will cite other reasons for why raising in this situation is good. Stuff like "for information" or "to stay aggressive" and "take control of the hand." But if a reason for making a play doesn't at least attempt to explain how you make more money off of it, it's possible that it's not the best reason. What information do you get from raising, and how are you going to use that information to play the hand any differently?
"Staying aggressive" is the tool, not the goal. Playing an aggressive style is recommended because it generally wins the most money, but the formula "aggressive = win most money" is not automatically true.
But taking control of the pot may be a good reason. It can be good, if we decide to check behind on the turn when we miss our flush. Unfortunately, such a move tends to make our hands very obvious to all but the blindest hand readers, but that may still be okay. So if we're somewhat certain that the big blind won't make it three bets and then lead the turn, raising the flop may be good - if we're also happy to check behind on the turn when we miss.
PokerStars 3/6 Hold'em (6 handed)
Preflop: Hero is UTG with 9♠, A♠.
Hero raises, MP 3-bets, 4 folds, Hero calls.
Flop: (7.33 SB) 8♠, 6♠, 2♦ (2 players)
This is about the best flop we could hope for. When MP made it three bets before the flop, it's clear - against all but the most aggressive or tricky opponents - that we're behind his range. Very few will make it three bets with less than A-J. Of course, an ace would perhaps have given us the best hand - he may have a big pocket pair - but we wouldn't feel too comfortable playing such a hand since a lot of his range includes aces with bigger aces than ours. So here we are, with overcards on a ragged flop and the nut flush draw. What should we do?
Let's establish something before we look at our options: We are not in bad shape, here. If we think he has a pocket pair 77 or larger, or AJ or better, at the minimum, we are just slightly worse than 50/50 to win this pot. Poker Stove says 45%. There is no (reasonable) set of hands that our villain will go 3 bets with preflop that we can currently beat, however. Now let's look at our options.
Given that we have an average equity of 45%, betting and raising on this flop won't cost us much. We only "lose" 5 cents of every dollar that we put in, which is fairly cheap if we can reap some other rewards, such as deception or fold equity (fold equity comes from our opponent folding a hand that has some chance of beating ours). However, we have no direct fold equity on this flop. There's absolutely no hand that an opponent will 3-bet with preflop and then fold to a rag flop donkbet. I know, I know, you should never say never, but realistically speaking, our opponent will virtually never give up right here on this flop. Of course, he may just call now and fold on the turn but we can't really know that yet. If he just calls the flop, it may be as a slowplay with a big pocket pair, where he plans on raising us on the turn. So if it's fold equity we're after, we need to bet both the flop and the turn - and possibly even the river. While we're in great shape on this flop (again, about 45% to win) this is not the case if the turn is not a spade. All of a sudden we're reduced to 20% equity, and now putting in big bets is going to be expensive.
Being out of position, fold equity is not going to come cheap in this hand. For betting to be correct, we need some other benefit to make up for the 5 cent loss. What about deception? Deception can make us a lot of money if our opponent will make big mistakes later on in this hand because he doesn't suspect a flush (when we hit). For instance, if we lead out on this flop and he decides to slowplay a hand like AA or KK, and then raises us on the turn, he will almost certainly pay us off dearly the times we hit our flush. That would certainly be worth the 5 cent loss right here, right now.
Here's the problem with deception, though: It requires that we're actually as sneaky as we think we are. Consider this: What kind of hand is our opponent going to put us on when we decide to donk a ragged flop with two spades on it? In my experience, people tend to do this with (almost only) two kinds of hands: small/medium pocket pairs, and strong draws. If we fit this pattern, a thinking opponent with AA/KK is going to be able to play very well against us. So if we are to bet out here with our nut flush draw, we should do it often with other hands as well. Perhaps hands like A8, sometimes as "bluffs" with KQs, etc. An action isn't deceiving if it fits a pattern.
Betting out is a "strange" move in the sense that most people tend to check to the person who was last to raise preflop. For that reason, checking is a little bit like acting in position; he will (almost always) bet when we check to him and he has to do so without knowing what we are going to do. If we check to him and checkraise his continuation bet, that sends a powerful statement. A checkraise says "hah! gotcha!" in a way that betting out doesn't, and perhaps suggests that we have an overpair to the board or otherwise believe we have him beaten, or a strong draw, Checkraising is, I feel, more deceptive than betting out. When big hands collide - and both us and the villain raised preflop, so this situation qualifies - the flop will often be checkraised. If he has a big ace and missed the flop, he will probably just call our bet. Some players are ultra-aggressive and will make it three bets with AK unimproved, but they're not that common.
Again, however, I must point to the fact that we're not a favorite to win. If we checkraise - and willingly take a slight direct loss - we must have a way to make up that loss later on in the hand. Are we being deceptive? Do we have fold equity? As before, I believe we cannot trust fold equity to make this a profitable play. Most hands that beat us will go to showdown on a flop like this, believe it or not. You may argue that not all players will call a flop checkraise and turn AND river with just AJ, but I will argue back that players who make it three bets with them preflop most often do. Not always, of course, but we will lose a lot of money all those times that he doesn't fold, or has a really big hand and play back at us.
We are also more or less committing to leading out on the turn, as well. That is going to be expensive for us every time that the turn is not a spade since we do not figure to hold the best hand for any other card (barring maybe an ace or a nine), and since we will sometimes be raised on the turn and forced to call, as we will have ample odds to try to hit our flush on the river. Sure, we can reserve the right to checkraise the flop and then check a non-spade turn but then that is something that needs to be done only occasionally. If this is how we play our nut flush draws every time we're out of position, this will be the first and last time this particular opponent will ever fall for it, if he takes notes. How to play deceptively and mix up your game is not the scope of this article series, however.
I'm going to suggest that checking with the intention of raising is not the most profitable play. Then what is?
This is what a real beginner would do. They'd flop a nut flush draw, figure "hey, I might hit a flush on the next card!" and then happily take one off. It's cautious. It's passive.
In today's online games, especially the shorthanded ones, players rarely fold big hands because the games are so aggressive that they get raised and re-raised with air often enough to make calling any heads-up action down with AK unimproved. Without fold equity and without anything particularly good coming from disguising our hand by playing it like we think we have the best hand, we can just call when we can't fold. Clearly, folding is not an option since we have a draw to the nuts and more than ample pot odds as incentive.
Here's the irony, though: Check/calling the flop with the nut flush draw is so rare these days that it's probably doing a better job disguising your hand than betting or raising ever would.
And that's our conclusion: We do not have sufficient equity to make betting and/or raising profitable on its own on the flop, so to warrant putting in more money than we have to, we must find other benefits. I do not believe these benefits are enough to make it more profitable than the obvious play - checking and calling.
Sometimes poker is easy. Don't make it harder than it has to be.
PokerStars 5/10 Hold'em (6 handed)
Preflop: Hero is UTG with K♥, J♥.
Hero raises, 3 folds, SB 3-bets, 1 fold, Hero calls.
Flop: (7 SB) T♠, A♣, 3♠ (2 players)
SB bets, Hero...
I made a really long introduction to the last hand, but I'm hoping to make some of that back now. I'm not going to explain all about equity and such again, but simply point out that we do not have the best hand here. However, there are a few things that are drastically better for us in this hand than in the last one:
The third partially follows from the second, but not only. That ace may well have helped him (it didn't directly help us) so if he's playing a hand like AK or AQ or even AA, we're looking at quite some action. Now, all we realistically have is an inside straight draw. Some of the time, he will have 99, JJ or QQ, granting us a three or six extra overcard outs, but these outs are really not worth much.
We're getting 8:1 on calling, and we're only about 10.5:1 to hit our inside straight. Hopefully you realize the importance of implied odds in a situation like this, though, that we stand not to win just the bets in the pot right now, but often many more bets from our opponent. It's surely a mistake to fold in this spot.
But do we raise?
As I said above, we do not have the best hand. A raise in this situation is not "for value" as our equity in this hand is only somewhere around 20% at best. A raise costs us a lot of money - so can we make that money up elsewhere?
First and foremost, we're in position. This factors in when we raise and makes the raise a bit "cheaper" than it would be otherwise. If our opponent has a really big hand (TT, AA, AK), he will often slowplay it on this flop and attempt to checkraise us on the turn. But we're in position; we can choose to take a free card on the turn if we miss (and, in fact, if we raise and get called we should take a free card on the turn). This is worth quite a lot, and makes the relative price for a raise go down a little.
The unfortunate thing about taking the free card on the turn, however, is that kills our fold equity. Some of the time, our opponent will call a flop raise and fold the turn with his weaker hands like 99 and JJ, but not if we check behind. I still think that taking the free card is better than betting again (and opening ourselves up to being checkraised) but it's a danger that we need to consider. Sometimes, albeit rarely, we will be up against an opponent who immediately folds his medium pocket pairs when we raise an ace-high flop. We did, after all, raise preflop. If you're in villain's shoes and get raised on this flop, wouldn't you feel that an ace is a very likely holding?
All that said, raising is a play that is only useful if we play our big hands fast as well on a flop like this, e.g. AQ and TT. If we routinely smooth call flops with big hands, then a thinking player will soon become aware that we only raise with mediocre hands, and be quick to adjust. So while raising this flop may be good, it's only feasible is our standard play is to raise with very strong hands.
The more passive play. As I've pointed out, we do have the implied odds to warrant a call. We miss out on the chance of raising for a free card on the turn - a play that may fail anyway if our opponent decides to 3-bet and lead the turn - but we will sometimes get a free card anyway. Sometimes, our opponent will give up (and call down) with a hand like KK and similar when we call the flop, when he's convinced that we sucked out on him with some ace-high hand. When he checks the turn, we check behind.
If we call this flop we must be prepared to fold a non-queen turn. We are getting 8:1 now on the flop, but on the turn we will only get 5.5:1. This is not good enough for us, and we will need to give up.
As with the last hand, I recommend calling as the standard play, but on the other hand, I'm going to strongly recommend raising as an occasional mixing-it-up play.
If you're up against a player who 3-bets very lightly preflop, you may consider raising just to avoid being pushed around too much. There are some players who are extremely aggressive preflop with (sort of) semi-bluffing hands like 98s and the likes, and they will often give up if you play back at them on an ace-high flop. And remember, if he has any hand that has more than five outs against you (basically any hand combination not including a K or a J), you will be happy that he folds. He's technically getting correct odds to call but doesn't realize it, so he makes a mistake in folding. This is great for you. But, again, this only applies if your opponent is very aggressive preflop with hands that you clearly beat. If you think he has a hand that's too strong for him to fold, raising is not the best move since the benefit of taking a free card alone is probably not enough. You need to compensate for some of the cost of raising by occasionally gaining some fold equity.