Tuesday, June 19, 2007

Defending late position raises

Haven’t posted in a few days, thanks largely to my friends boat party on the river Thames over the weekend. Think I drank the best part of 2 bottles of wine early Saturday evening and was thus completely incapacitated for the rest of the night, and also the weekend!
Been meaning to submit a strategy post for a while though, so have included below my latest idea on defending late position raises. As ever, any feedback will be appreciated (*hint hint*).

The situation: 6-max NLHE. You limp in early with a med/small pair or SC. As usual in aggressive short-handed games, the cutoff or button raises 4BB. The blinds fold, and you are the only caller. The flop comes Kh 7s 3c, and there is almost 10BB in the pot.
Having missed the flop completely, you check. The button c-bets (say 8BB), as expected. Now, you check-raise. Most of the time, this will elicit a fold, and you will win the 18BB pot. Let’s look at why.

Basically, this play is based on receiving the correct flop (more on this later), and the hand range your opponent will raise with. Let’s think about what you opponent is raising with here (either in the cutoff or on the button), assuming they are fairly tight.
AXs ( X = K-8 )

Knowing what we do about the number of ways these hands can be dealt, we can determine the following numbers:
AA-88 => 7 * 6 = 42
AKo-ATo => 4 * 12 = 48
AXs ( X = K-8 ) 6 * 4 = 24

Total # ways to be dealt a raising hand: 114.
Now we factor in the fact that there is a K on the flop, and adjust this number accordingly: 107.

The importance of the K-high uncoordinated flop now becomes apparent. We now need to look at the number of above raising hands which are NOT compromised by this flop. These are as follows:
AA, KK, AK giving a total of 21 (= 6 + 3 + 12).
This list is short precisely because the flop contains a single high card, and is uncoordinated. Thus drawing hands can effectively be eliminated from the range, as calling a re-raise with only a backdoor draw is extremely uncommon.

So, in this example, out of 107 solid raising hands, only 21 will be strong enough to continue after the flop. So what percentage of hands are potentially crippled by this flop?
(107-21) / 107 * 100 = 80.37383 !!!
This means that 80% of the time, the raiser’s hand has been compromised and faced with a check-raise they should give up there and then. If that isn’t a good spot to bluff check-raise, I don’t know what is!
I must stress though the importance of the high-card being a K. If it is a Q, the range of hands that are still in good shape increases dramatically, to the point where the move is almost a coin-flip in terms of odds. Save your money for those occasions where you will have clearly the best of it.

There are several caveats to this play, such as your opponent being able to fold an underpair, them not hitting the middle flop card to make a set, always making a c-bet, and so on. I will not go into into these, but be aware there are situations and exceptions where the check-raise will not elicit a fold, and in these situations you should shut down immediately unless you improve dramatically.

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