This time, I would like to summarize the points to keep in mind when playing a gutshot straight draw.
◆Key points for gut shot straight draw◆
A gutshot straight draw is a straight draw with four outs, and a gutshot draw on the flop has an 8.5% chance of completing a straight by the turn and a 16.5% chance of completing a straight by the river.
●Strength of the draw
There are two types of strength of the draw here: the strength of the completed hand, and the number of outs.
For example, let’s compare the case where you have and the case where you have 
on a board of 
① Equity of about 20% against your opponent
Even if you complete a draw with few outs, there is a possibility that they will make a stronger straight, in which case the reverse implied odds will be large and losses will likely increase.
Pair outs against your opponent’s pair require a backdoor 2 pair or trips.
There is no backdoor flush draw, so it is difficult to semi-bluff.
② Equity of about 31% against your opponent
If you get an out to your straight, you will have a nut straight.
You have one overcard out against your opponent’s top pair, and two overcard outs against your opponent’s middle pair.
You have a backdoor flush draw, so it’s easy to semi-bluff on the turn.
As you can see, even with the same gut shot draw, there can be significant differences in equity and ease of play, so it’s important to be careful.
●Gutshot in the BB Straight Draw
A gutshot in the BB is a good hand for a semi-bluff check-raise.
Good draws with lots of outs, like flush draws and open-ended straight draws, have enough outs and equity to call against your opponent’s CB even when out of position,
but if you check-raise and your opponent 3-bet, those draws are pretty tough spots because you’re out of position.
So in this situation, a gutshot draw is suitable for a semi-bluff check-raise because it has a reasonable amount of equity and is easy to fold
against your opponent’s 3-bet. If you have a gutshot straight draw, you can easily fold against your opponent’s 3-bet, and if you get a backdoor flush draw on the turn, you can semi-bluff a double barrel, or if you complete your straight or hit an overcard, you can make a value bet.
And this check-raise is more effective against players with a wide open-raising range and a high CB probability.
Let’s look at some examples.
◇BB calls against open raise from BTN
On the flop of ①
On this flop, you have a gutshot straight draw and a backdoor flush draw.
You can check-call (float) the flop, but you have no showdown value, and if a high card comes after the turn, it will be difficult to bluff on the river.
If you check-raise here, you can put pressure on your opponent by double-barrelling with cards like the turn’s 6 (completes a straight), T (open-ended straight draw), or spade (flush draw).
On the flop of #2
On this flop, you have a gutshot straight draw and a backdoor nut flush draw.
You can check-call or semi-bluff because you have showdown value, A-high.
If you check-raise here, you can put pressure on your opponent by double-barrelling with cards like the turn’s 2 (completes the straight) or diamond (nut flush draw).
The turn’s A is often the best hand, so you can double-barrel for value or check-call.
On the flop # 3
On this flop, you have 2 overcards, a gutshot straight draw, and a backdoor flush draw.
If you check-raise here, you can put pressure on your opponent by double-barrelling with cards like the turn’s 9 (completes the straight), K (open-ended straight draw), or clubs (flush draw).
The turn’s Q or J is likely to be the best hand, and you can check-call since it has showdown value.
