Duality is supposedly the best intertype relationship. It’s interquadral and symmetrical, and is the relationship for when the valued functions are in opposite order. So for an ENTJ, the dual would be an ISFP.
There are several strengths of duality that makes it the optimal type relation, even though it might not look so initially.
First of all, and maybe most importantly, we have the dual-seeking function. Our dual-seeking, or inferior, is a function we want help with from other people. Our dual has this as their dominant function, their main program, so they have no problem whatsoever at providing this. The hidden agenda, or mobilizing function also plays a huge role. This is another function where we want help, but too much use of it is only annoying. Which is why it’s a lot better as a creative function for our dual, where it’s a tool they can provide when we feel the need for it, but doesn’t “live and breathe” it in the same way.
The second big thing that makes our dual a good match, is that they take care of our weak spots. Our weakest function, the point of least resistance, is a function we prefer to leave to other people. But at the same time, not to someone that would be up in our face with it. So because of this, it’s better if the other person has this function as an unconscious but strong process, which would be in their id-block, and specifically demonstrative. They make sure we don’t have to deal with the process ourselves, which is highly appreciated.
However, it’s important to note that this is a theoretical formula, and shouldn’t be applied too rigidly into real life.
The relationship is between:
INFP – ESTJ
ENFP – ISTJ
ISFP – ENTJ
ESFP – INTJ
ISTP – ENFJ
ESTP – INFJ
INTP – ESFJ
ENTP – ISFJ