Victor Gulenko introduced different subtype systems in the past. They are all based on subdividing the Jungian dichotomies into 4 categories:
1.) Accepting/Producing uses not 2 but 4 categories of Rationality/Irrationality. You can be very rational, quite rational, quite irrational or very irrational.
2.) DCNH also uses not 2 but 4 categories to describe Introversion/Extraversion. Very introverted, quite introverted, quite extraverted, very extraverted.
3.) His system with 8 subtypes introduces the Primary/Secondary dichotomy. So a third Jungian dichotomy is subdivided into 4 categories (depending on your DCNH subtype).
4.) Using 16 subtypes we just have to look at the four Jungian dichotomies and divide them into 4 categories each.
I am very introverted, very intuitive, quite logical, quite rational. So I am an INTj with an INFp subtype. I just wanted to clarify that because a lot of people on this forum are of the opinion
- that dichotomies are not important,
- that subtypes are not important
- or that subtypes have nothing to do with dichotomies.
Victor Gulenko, the most cited socionist after Augusta, works a lot with subtypes and dichotomies as you can see. So everyone who says that subtypes or dichotomies "are not socionics" obviously disagrees with the most important socionist...
But the more interesting point is: There is clearly a correlation between shape of face and subtype. I made 3 interesting discoveries during the last months and the fourth discovery will certainly come...
1.) The first thing I discovered was that subtypes with a strengthened conscious function have roundish faces whereas subtypes with a strengthened unconscious function have longish faces. See this thread. So you might start with this Roundish/Longish dichotomy if you are interested in Dichotomies & Subtypes & V.I.
2.) The next dichotomy I discovered some months ago was Angular/Soft. Subtypes with a strengthened base or demonstrative function have rather soft faces, subtypes with a strengthened creative or ignoring function have angular faces. The combination of Roundish/Longish and Angular/Soft makes it possible to diagnose DCNH subtypes by V.I. - but only if you are experienced enough and already know the main type of the person you want to type. Description and examples here.
3.) The third dichotomy I discovered some weeks ago. This one is necessary to determine Gulenko's 8 IE subtypes by V.I. - I think I'll call it Mathematical/Natural. Mathematical means a face looks really like a circle, a square, an oval or a rectangle. Natural means "angular circle", "rounded square", "piriform oval" or "broad rectangle":
role: angular circle
vulnerable: rounded square
mobilizing: piriform oval
suggestive: broad rectangle
See this thread for explanations and examples.
Currently I'm trying to find the fourth "VI dichotomy" to distinguish between 256 types by VI. This one is really subtle and it is very difficult to descibe because you need to know a lot of people of the same type...