In
poker to back door a
flush or
straight is when the last
two cards can make a player's
hand
"Ouch, I had a three of a kind but he made a back door straight"
In Texas Hold 'em what are the chances of getting a back door flush if after the flop we have a 3-flush?
We have 2 Hearts
And the board is H-S-C
3 Hearts are out, 10 remain in a deck of 47. The chance of hitting our Heart on the turn card is:
10
-- = 0.213
47
And the chance of hitting our 5th Heart is calculated the same way, there are 9 Hearts in a deck of 46:
9
-- = 0.196
46
The chances of both these events happening are:
0.213x0.196=0.0416
The chances of pulling off that elusive back door flush? 4%. The
implied odds better be good if your chasing that kind of
rainbow. This kind of analysis is important in
preparation for playing poker. Doing this at the table, is not an easy task, so doing it before the game is important. There are times when an unexpected turn of events causes you to
think fast at the table. If you were chasing this flush, and you thought your opponent was chasing the same flush, you'd know that neither one of you has a good chance of making it (since he has 2 of the hearts in his hand too...the chances of you getting the flush is now about 2.5%). That means if he has a busted flush at the end, so have you. But of course, he doesn't know that you have a busted flush, so now its time turn on bluffing mode (which can be reinforced earlier with a
semi-bluff raise on fourth street when a heart appears).