Saturday, April 17, 2010

The Importance of PreFlop Play

Something I do two or three times a year is analyze how my starting hands are faring in different preflop situations. For example, I look at how hands I’m raising first in from the button, cutoff, hijack, under the gun, and the small blind are faring. I look at how hands I’m defending from the big blind fare against opens from different positions. I also look at how hands I 3-bet from the small blind fare against button and cutoff raises. Etc, etc. These are all situations where I have a fairly substantial amount of data to work with and feel confident in the results. Based on the analysis I add or subtract hands from the various ranges. This process has contributed a great deal to my improvement over the past few years.

How important is preflop play? There are 169 starting hands in hold-em. 13 are pairs, 78 are suited hands, and 78 are offsuit hands. There are 12 ways to make an offsuit hand, 4 ways to make a suited hand, and 6 ways to make a pair. You’ll be dealt a specific pair like Aces once every 221 hands, a specific suited hand once every 332 hands, and a specific offsuit hand once every 111 hands. More on the math associated with all this is here

Now let’s assume the following plays are mistakes and that you make them:

Raising K2o, K3o, K4o, K5o from the button against typical blinds
*Not* raising Q8o, Q7o, Q2s, Q3s, Q4s, Q5s and Q6s against typical blinds

Let’s assume you lose the following when you play or don’t play these hands. These are approximations based on my data:

K5o (.03) BB/HD
K4o (.06) BB/HD
K3o (.09) BB/HD
K2o (.12) BB/HD
Q8o (.15) BB/HD
Q7o (.05) BB/HD
Q6s (.09) BB/HD
Q5s (.07) BB/HD
Q4s (.05) BB/HD
Q3s (.03) BB/HD
Q2s (.01) BB/HD

Last, let’s assume you’re going to play 1000 hands of 3-handed poker. That means over the course of these hands you’ll be on the button roughly 333 times. So how much do these mistakes cost on average over these 1000 hands?

Since you’ll be dealt a specific offsuit hand once every 111 hands on average you’d be dealt each offsuit hand 3 times on the button and lose:

.03*3 + .06*3 + .09*3 + .12*3 + .15*3 + .05*3 =.09+.18+.27+.36+.45+.15 = 1.5 Big Bets

And you’ll be dealt a specific suited hand once every 332 hands on average or about 1 once on the button and lose:

.09+.07+.05+.03+.01 = .25 big bets

All that adds up to a net loss of 1.75 Big Bets over the 1000 hands. That might not sound like a whole lot but consider that’s .175 big bets per every 100 hands. Now consider that some of the best limit hold-em players average 1 big bet per hundred hands, that’s 17.5% of their profit! Also consider that these are a just a few of hundreds of possible mistakes people can make. Imagine they are 3-betting incorrectly from the small blind and defending incorrectly from the big blind over this 1000 hand sample and they could be giving up quite a bit.

Nobody plays perfect preflop, it’s nearly impossible. But the idea is to make as few mistakes as possible. The best way you can do this is to analyze your own data and see how you’re faring with hands in certain situations. This should give you a general idea of what hands are playable under normal or average conditions. You then can make in-game adjustments based on table dynamics. For example, if you have very tight blinds, you can add in all those hands that were small to marginal losers from the button. If you have loose, aggressive blinds, you can drop all the hands that are small winners. Another example is defending from the big blind against the various positions. I know what my default defending range is based on a typical raiser’s RFI% from each position. If the raiser is atypical, I’ll cater my range to them. I also account for the player’s postflop ability when deciding to defend borderline hands. In extreme cases, I’ve played against opponents who play so poorly postflop that I defend 100% of my hands from the big blind regardless of what position they’re raising from. So use your data as a baseline and go from there. It’s not an exact science and you won’t get every situation right. The most you can do is to consider all the information available and make the best possible decision based on it.


  1. Great post Tony! I really really like your blog entries :)

    I remember seeing something like a "Rake in BB" column in your HEM screenshots. Have I just missed it in HEM or is it customized?

  2. Thanks, glad you like it.

    That stat is a custom stat a friend made.

  3. Nice post again!

    You are a US resident, right?

    Could you make a blog sometime within this month or next month about your thoughts on the UIGEA? And what you can predict might happen for deposits and cashouts? also the difficulty of the game?


  4. I haven't followed the UIGEA too closely over the past year, I've just heard the implemtation has been pushed back a few times. My thoughts would just be speculation so I'm not sure if they'd have any value to you. That said I doubt much will change when it is implemented in terms of deposits/cashouts or difficulty of the game. I think most of the damage has been done already.

  5. You are not worried?

    Do you have like an offshore bank acct or something?

  6. I'm not worried, I think we've seen the worst of things as far as the UIGEA is concerned but I'm no expert and haven't been keeping up with it as I said.

    I have a Bank of America account and have never had any problems with it.

    The worst case scenario for online poker would be that it's made illegal and if that were to happen I'd move out of the country.

  7. How can u explain your w$sd less then 50, wtsd >40 but profit still good enough. Is it dos'nt working at low limits? Is it because huge rake there or something else?

  8. I think it has to do more with the fact that the ranges get wider and wider as you move up in limits. So, you'll be getting to showdown a lot more with marginal hands and bluffs then you would against tighter ranges. There may be some other factors as play as well, I haven't thought a whole lot about it.

  9. WTSD and W$SD have an inverse relationship.

    I play .25-.50c lhe and b/c of the multiway flops, my average is 37/55. Before when i was making a lot of ace-high call or other marginal call downs, i had 35/57 a lot of times.