Poker Lesson 26

Evaluating the flop in hold'em, part 6: The Rule of 4%

I have touched upon drawing hands in the previous lesson, and it is time to expand on this subject – and to pay attention to the mathematics of various situations. In reality, a lot of starting hands you will decide to "go to war with" before the flop may be considered drawing hands. Not only does the term drawing hands cover obvious hands you primarily hope to flop a straight or a flush (or even a straight flush) with, such as J-10 and 8-9 in the same suit, but any hand containing two high cards, such as A-K, A-Q, A-J, K-Q and K-J may be considered a drawing hand: in order to win the pot, such a hand almost always needs to improve to at least top pair, and preferrably two pairs or trips. Cards containing a medium-to-high pair, such as 8-8 up to A-A, instead have a better chance of winning on their own without improving on either the flop, the turn or the river. With the flop, many of your starting hands will improve considerably: with J-10 and a flop of Q-9-2, you now have a strong draw to a straight – if either a K or an 8 falls on any of the two last cards of the board, you have hit your straight. With A-J in diamonds, and another two diamonds on the flop, you have a draw to a flush; and with A-10 and a flop of K-10-3, you have hit middle pair and have a draw to two pairs (if an A falls) as well as to trips (if another 10 falls) and even a "backdoor draw" to a straight (if both a Q and a J fall, in whichever order, on the turn and the river). Or you may have 9-10 with a flop of A-9-10, and wonder what your chances are of hitting a full house with the help of another 9 or 10. Here is an important rule of thumb: With two cards to come (turn + river), your chances of improving your hand are approximately 4% per card which will help you. For eight or more available cards, you must round the number down somewhat. An example: You have A-10 of diamonds in hand, and the flop is 9 and 3 in diamonds, plus the 6 of clubs. If another diamond card falls, you have hit the top flush. What are the chances of this happening? Well, since there are nine more "unknown" diamond cards in the deck that will help you, your chances of hitting that flush are 9 x 4% = 36%. (In reality slightly lower, 35%.) Another example: You have K-Q in hand, and the flop is K-Q-6 with two clubs. (None of your starting cards is clubs.) You have flopped a strong two pair, but are at risk against an opponent holding for example A-5 of clubs (= draw to top flush) or J-10 (= draw to an open straight), both being hands higher than your present top two pairs. What are your chances of hitting a full house, on either the turn or the river? Since there are four cards left in the deck which will help you here (the two remaing Kings and the two remaining Queens), the chances are 4 x 4% = 16%. (In reality 16,5%.) Notice that this rule of thumb assumes that you will look at BOTH the turn and the river = TWO more cards, not just the next card! Also, this way of figuring out your chances to improve does not cover when you need TWO more cards, not just one, which must both be "right". If you hold A-Q of diamonds and the flop comes with just one diamond card, you can only hit your flush if both the turn and the river are diamond cards = a chance of 3,3%, which corresponds to odds of 29 to 1 against. This is a wholly different situation! The improvement percentage your calculations yield (called your "improvement odds" or "card odds" in poker parlance) must also be seen in relation to the pot odds, but this is an important subject for several future lessons. Keep in mind also your ACTUAL chance of winning the pot, which may or may not be the same as hitting one of the cards you need. If you have A-J of diamonds in hand and the flop is Q-7-3 with two diamonds, and the turn then is Q of spades and the 7 of diamonds, you will have hit your flush but lose to any Q or 7 in another player's hand, as he or she will now have hit a full house. Beware of "false improvements", which help you but help another player even more!

DAN GLIMNE