Poker Lesson 28

Evaluating the flop in hold'em, part 7: Different types of flush draws

In an earlier lesson, I mentioned your chances of improving a flush draw once the flop has landed on the table (= you have four cards of the same suit, after the flop, and only need one more card of the same suit): they are 35%, corresponding to odds of 2 to 1 against. Or to put it yet another way, you will make your draw one time in three. However, this figure assumes you will look at BOTH the turn and the river (the fourth and the fifth card on the board).

If you need TWO more cards to hit your flush, meaning that you have a "three-flush" after the flop so that BOTH the turn and the river must be of the suit you need, the chance of this occurring is only slightly over 3%: corresponding to odds of 29 to 1 against. Such a "backdoor flush", as it is called, will occur every now and then, but is not realistic to hope for!

A third type of flush draw that merits evaluation is the rare "unexpected flush draw", when a single-suit flop lands and helps you. Let us assume you hold the King of spades and the Queen of diamonds, and have called from late position pre-flop in an unraised pot (often a reasonably sound move, by the way). Now the flop lands on the table: 9-5-2, all in spades. Good news! You now have four cards to a flush draw! The chances of your hitting that flush are of course the usual 35%, just as if you had had two spade cards in hand and the flop had given you two more spade cards and, let's say, a hearts card.

However, this situation is also bad news for you: if one more spade card hits on the turn or on the river, and you make your flush, another player who happens to have the A of spades will now have a higher flush than you do! As the saying goes in poker, there is nothing more expensive in poker than placing second in a pot.

Beware of flush draws which are not to the highest possible flush! (In the above example, you would be "safe" if the A of spades appears on the turn or on the river, since you are holding the K of spades and no other player could thus have a higher flush.) This is not the same as saying that you should always give up those flush draws, of course: but instead you must pay attention to the possibilities. Holding the K of spades in the above situation and hitting the flush, you will win more often than not because the odds are against another player holding precisely the A of spades, However, if you are holding only let's say the J of spades, you must tread much more carefully if and when hitting the flush: now you will not lose only to the A, but also to the K and Q of spades – and the risk of another player holding any of those three cards is far greater than the risk of him/her holding precisely the single A of spades. The lower the flush you are drawing to, the greater the risk of your hand losing in a showdown to another, higher flush.

There is also another risk with a single-suit flop giving you an unexpected flush draw: while you chase the draw during the betting after the flop and perhaps after the turn too, another player may already have flopped a finished flush (holding two cards in that same suit) which could be costly for you.

If you hold two cards of the same suit and flop a flush draw, with another two cards of that same suit on the flop, at least no other player can have a finished flush right then – but once again you must tread carefully if you do not have the draw to the highest possible flush. Even K-Q in spades will lose to 5-A in spades in another player's hand, when three more spade cards appear on the table to complete both flushes.