Poker advice and news from Dave Colcough of Bet365 Poker
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Post Flop Probabilities Part One
Written by: Dave Colclough (2004-09-20 22:15:57)
The last couple of articles concerned pre-flop probabilities.
These are most relevant to NLH tournament play. This is because most chip
movement occurs pre-flop in NLH tourneys, whereas, with Limit Hold 'em and Pot
Limit Omaha, most of the action takes place post flop. The next couple of articles
discuss post flop odds and probabilities. These are equally interesting to the NLH player,
but they will have less opportunity and situations to take advantage of this knowledge.
Possibly the most useful probabilities are those surrounding a flush draw.
If you hold two cards of the same suit, you will flop a made flush slightly
less than 1% of the time. If you are all-in before the flop, the chances of completing
your flush with all five cards are somewhere around 6%. More useful though is the situation
when you flop four to your flush: two hearts in your hand with two hearts on the flop,
or one heart in your hand with three on the flop.
Many NLH players will commit their whole stack heads up in this
situation, but the odds say that really you shouldn't. You will only complete the flush
around 35% of the time. So if a player has moved all-in, in front of you, for a large
bet of greater than pot size, the correct play is probably to pass. You are not getting
good pot odds. You will often see players making bad calls in this situation. It is of
course different if you move all-in first to speak. You may only win the pot a third of
the time if someone calls, but of course you may win the pot 50% of the time, uncontested,
if everyone should pass.
In Limit Hold 'em of course, you will rarely win the pot uncontested,
but the pot odds will be different. In many ways Limit Hold 'em is much more complicated
here. In a $2/$4 game, four players may have seen the flop. The player in front of you
bets $2 on the flop, and you can easily justify the pot odds as you are now calling $2
against a $10 pot. However, there are variables to consider: how much more you may have
to call to see the final two cards, and how much more can you win if you hit the flush.
Firstly, a player may raise behind you and the original bettor may re-raise. Now you are
risking $6 against $20. The odds aren't as good but are still favourable. But of course,
the flush may not arrive on the turn, and you may have to call another $4. Now the risk
is $10 against $28, or possibly $10 against$24 if play becomes heads up. You are in fact
still getting pot odds, but only just. The second variable is of course when you hit the
flush, how much will you get paid? If the player will call a $4 bet on the end, or better
still, a two bet situation may emerge, then you are of course reaping the real benefits of
your draw. Flush draw flops are usually a profitable venture in Limit Hold 'em.
Remembering all these situations and odds isn't as hard as it
initially looks. You will constantly hear players refer to 'outs'. A flush draw is 9 outs.
If you have an open ended straight draw, you have 8 outs. Most top players just count their
outs, and know the probabilities of hitting these outs. Next weeks article will include the
'outs' table and further explanation.