What exactly is an open straight
By Jerry “Stickman” Stich
Look at the strategy for just about any video poker game and you will find two different types of straight—an open (or more accurately open-ended) straight and an inside straight. The terms open and inside also apply to straight flushes which are simply straights consisting on one suit.
Most players, no matter how casual their play may be, know somewhat instinctively that open straights are good and inside straights are not so good. They phase “never draw to an inside straight” is classic old school poker advice.
According to the Poker Dictionary available at www.pokerzone.com, an open-ended straight is deﬁned as follows: “A sequence of four cards of consecutive rank in which there are two possible card ranks that will complete a straight; as opposed to a one.”
Using this definition a 5, 6, 7, and 8 is an open straight. The 2, 3, 4 and 5 is also an open straight as is the 10, jack, queen and king. This is true because the straight can be completed by drawing a card on either end of the sequence. In the first example a 4 or a 9 would complete the 5-card straight. In the second example an ace or 6 would complete the 5-card sequence. And, in the last example, a 9 or an ace would complete the 5- card sequence.
Many video poker players think of an open straight as any sequence of cards without a gap. They might consider an ace, 2, 3, and 4 as an open straight.
It is not.
It is true that this is a 4-card sequence that does not contain a gap, but it can only be completed by drawing a card at one end of the sequence—a 5. For this reason, this sequence is considered an inside straight. Rather than thinking ofan open four-card straight (or straight flush) as a sequence of cards without a gap, it is better to think of it as a sequence of cards that can be completed at either end ofthe sequence. Anything else is an inside straight.
What about 3-card straights?
The same rules apply. Just because the three cards are in sequence does not automatically qualify the hand as an open straight (flush). A hand containing a 5,6 and 7 would be an open straight (flush). It can be filled by drawing the 3 and 4, the 8 and 9 or the 4 and 8. In other words it can be completed by drawing two cards on either end, or one on each end.
A hand containing a 2,3 and 4 would not be an open straight (flush). It can be completed by drawing a 5 and 6, and by drawing an ace and 5, but there is only one slot at the low end of the sequence—the ace.
The same rules apply to a 2-card straight (flush). A hand containing a 5 and 6 is an open straight (flush) because it can be completed by drawing the next or previous three cards in the sequence.
Specifically, drawing a 2, 3, and 4 or a 7, 8 and 9 will complete the straight (flush). Drawing a 3, 4 and 7 or a 4, 7 and 8 will also complete the straight (flush).
What about a hand containing a 3 and 4? It can be completed by drawing the 5, 6, and 7. It cannot be completed by drawing the three lower cards in sequence, however and only the ace and 2 slots are open.
Hopefully the above explanations and examples are clear to you. Rather than to define an open straight (flush) as a series of cards in sequence, it is much better to define an open straight (flush) as a hand that has a series of cards in sequence AND can be completed by filling either end with the total number of slots remaining after discard.
The above definition works fine as long as the game being played is a standard (non-wild card). If playing a wild card game such as deuces wild, the definition of an open straight (flush) has an additional requirement. That requirement is: a wild card cannot be used to fill the gap and create an open straight (flush). For example, in deuces wild a hand containing a 2, 6, 7, and 8 is considered an open straight (ﬂush). However, a hand containing a 2, 5, 7, and 8 is not considered an open straight (flush) because the missing 6 cannot be filled by a wild card to be considered an open straight (flush).
In order to make video poker play as profitable as possible, dealt hands must be interpreted properly. Improperly determining an inside straight (flush) as an open straight (flush) will dramatically reduce the expected return. Take the time to determine that what you are seeing is actually what you think it is. That will pay dividends in the long run.