In online poker, the inside straight draw, also known as a gutshot draw, is four cards forming a sequence of five, a straight, with one of the middle three cards missing.
For instance, 8-9-10-J-Q is a straight. Assume that you take away the 8 or the Q. And then you have an open ended straight draw or an outside straight. Any 8 or any Q from the remaining of the 48 cards can complete the sequence. Hence, if you draw a card randomly from the rest of the deck you have one chance in six of finishing the straight.
But if you take away the 9, 10 or J, only that rank can complete the straight. Only four of the 48 remaining cards give you your straight. It is just one chance in 12.
It is also known as an inside straight if you have J-K-Q-A or A-2-3-4. In both cases, just one rank can finish up the straight, as you are not permitted to go ‘around the corner’ in poker online.
The rules to notice:
The rule to not ever draw to one comes from draw poker. This is the only form of poker in which a poker player draws cards. In all forms of poker online having an inside straight with cards to come is less valuable. Less valuable than an open minded straight draw. However as a few of the cards are disclosed, it has a few surprise values. This makes up for a few of its lower probability. For instance, in Hold’em, if the board is Q-8–2 and you hold JT, only a 9 can make your straight, but if a 9 shows up, you are more probable to get a call than if the board had been Q-9–2 and an 8 showed up.
In draw poker, but, all your cards are hidden. Thus, there is no strategic reason to make a play with an inside straight. You can just as well wait for an open-ended straight draw for the same play.
Another problem is mathematical. If you draw one card in draw poker, the other players will figure you almost certainly for two pair, then three of a kind, then a flush draw, then a straight draw. There are four cards which improve two pair or three of a kind, to a full house or possibly four of a kind. Those hands are all better than a straight. There are nine cards that perk up a flush, and again it’s better than a straight. An open-ended straight draw has eight cards to perk it up. But an inside straight is tied for the fewest cards which perk it up, and it’s the weakest hand if it develops. It has zero benefit over those other hands.
Good luck for playing poker at the tables!