Socionics has two ways of writing a type. Most of the community now uses three-letter codes like LII and ILE. Older texts, and plenty of newcomers, use four letters like INTj and ENTp. People argue about which is better, usually on the grounds that the four-letter version looks too much like MBTI.
That worry is fair, and I come back to it at the end. But the four-letter code does one thing the three-letter code doesn't: it shows you the small groups at a glance. Every club, temperament and Reinin dichotomy sits in a fixed pattern of letters. Once you know the patterns, you can sort a room of type codes without working through anyone's function order.
This guide sets out every one of those patterns. It covers thirteen small-group systems, from clubs and quadras to thinking forms, and all fifteen Reinin dichotomies.
What the four letters mean
The four letters are the four Jungian dichotomies, always in the same order.
| Position | Letters | Meaning |
|---|---|---|
| 1 | E or I | Extraverted or introverted |
| 2 | N or S | Intuitive or sensing |
| 3 | T or F | Logical or ethical |
| 4 | j or p | Rational or irrational |
The last letter is lowercase on purpose. In Socionics, j means the leading function is rational (logic or ethics) and p means it is irrational (intuition or sensing). It says which kind of function leads, for every type.
That is not what J and P do in MBTI. There, J and P describe the extraverted function, so for introverts they point away from the dominant one. An MBTI INTJ leads with introverted intuition, which is an irrational function. In Socionics terms that is a p type. Read by functions alone, MBTI INTJ lines up with Socionics INTp (ILI), not INTj (LII). The descriptions differ between the systems too, so never convert a code by rule. The lowercase letter is there to stop you trying.
Here are all sixteen types in both notations, by quadra.
| Alpha | Beta | Gamma | Delta |
|---|---|---|---|
| ILE · ENTp | EIE · ENFj | SEE · ESFp | IEE · ENFp |
| LII · INTj | IEI · INFp | ESI · ISFj | EII · INFj |
| ESE · ESFj | SLE · ESTp | LIE · ENTj | LSE · ESTj |
| SEI · ISFp | LSI · ISTj | ILI · INTp | SLI · ISTp |
Two letters, one group
Six of the small-group systems need only two letters. A four-letter code has exactly six pairs of positions, and each pair gives one system. Read the two letters and you have the group.
| System | Letters | Pattern | Group | Types |
|---|---|---|---|---|
| Stimulus groups | 1 and 2 | EN·· | Distinguished | ILE, EIE, LIE, IEE |
| IN·· | Confident | LII, IEI, ILI, EII | ||
| ES·· | Esteemed | ESE, SLE, SEE, LSE | ||
| IS·· | Hopeful | SEI, LSI, ESI, SLI | ||
| Communication styles | 1 and 3 | E·T· | Firm | ILE, SLE, LIE, LSE |
| I·T· | Cool | LII, LSI, ILI, SLI | ||
| E·F· | Passionate | ESE, EIE, SEE, IEE | ||
| I·F· | Sincere | SEI, IEI, ESI, EII | ||
| Temperaments | 1 and 4 | E··p | Flexible-manoeuvring | ILE, SLE, SEE, IEE |
| E··j | Linear-assertive | ESE, EIE, LIE, LSE | ||
| I··p | Receptive-adaptive | SEI, IEI, ILI, SLI | ||
| I··j | Balanced-stable | LII, LSI, ESI, EII | ||
| Clubs | 2 and 3 | ·NT· | Researchers | ILE, LII, LIE, ILI |
| ·NF· | Humanitarians | EIE, IEI, IEE, EII | ||
| ·ST· | Pragmatists | SLE, LSI, LSE, SLI | ||
| ·SF· | Socials | ESE, SEI, SEE, ESI | ||
| Perception groups | 2 and 4 | ·N·p | Receptive | ILE, IEI, ILI, IEE |
| ·N·j | Circumstantial | LII, EIE, LIE, EII | ||
| ·S·j | Thorough | ESE, LSI, ESI, LSE | ||
| ·S·p | Flexible | SEI, SLE, SEE, SLI | ||
| Argumentation styles | 3 and 4 | ··Tp | Restructurer | ILE, SLE, ILI, SLI |
| ··Tj | Constructor | LII, LSI, LIE, LSE | ||
| ··Fj | Guardian | ESE, EIE, ESI, EII | ||
| ··Fp | Diplomat | SEI, IEI, SEE, IEE |
This is where the four-letter code earns its keep. To find the Researchers among three-letter codes, you have to spot L and I in the first two letters of LII, ILE, ILI and LIE. In four letters they are simply the codes with NT in the middle.
One letter, then a pair
Four more systems fix one letter, then accept either of two letter pairs. Check the fixed letter first, then which pair the rest of the code makes.
Take SEE, written ESFp, and its romance style. The fixed letter is S. The rest of the code gives E with p, one of the two pairs that make a type static. S plus static is the Aggressor romance style.
| System | Fixed letter | Group | Patterns | Types |
|---|---|---|---|---|
| Romance styles | N or S | Infantile | EN·p or IN·j | ILE, LII, IEE, EII |
| Careful | ES·j or IS·p | ESE, SEI, LSE, SLI | ||
| Victim | EN·j or IN·p | EIE, IEI, LIE, ILI | ||
| Aggressor | ES·p or IS·j | SLE, LSI, SEE, ESI | ||
| Stress resistance | j or p | Viscous | ·NTp or ·SFp | ILE, SEI, SEE, ILI |
| Trainable | ·NTj or ·SFj | LII, ESE, ESI, LIE | ||
| Fragile | ·NFj or ·STj | EIE, LSI, EII, LSE | ||
| Flexible | ·NFp or ·STp | IEI, SLE, IEE, SLI | ||
| Implementation groups | T or F | Perfectionist | ·NTp or ·STj | ILE, LSI, ILI, LSE |
| Resultator | ·NTj or ·STp | LII, SLE, LIE, SLI | ||
| Implementer | ·NFp or ·SFj | ESE, IEI, ESI, IEE | ||
| Finisher | ·NFj or ·SFp | SEI, EIE, SEE, EII | ||
| Planning styles | j or p | Free | EN·p or IS·p | ILE, SEI, IEE, SLI |
| Stable | IN·j or ES·j | LII, ESE, EII, LSE | ||
| Staged | EN·j or IS·j | EIE, LSI, ESI, LIE | ||
| Variant | IN·p or ES·p | IEI, SLE, SEE, ILI |
Each pair is half of a Reinin dichotomy, covered below. Romance style is N or S plus static or dynamic. Stress resistance is j or p plus democratic or aristocratic. Implementation is T or F plus tactical or strategic. Planning style is j or p plus carefree or farsighted.
Groups that need the whole code
Three systems don't sit in any one or two letters. Each stacks two of the earlier rules, so the four-letter code gives them away more slowly. These are the places where the three-letter code is often the quicker read.
Quadras pair one static club with one dynamic club. Static is E with p or I with j; dynamic is E with j or I with p. LIE, written ENTj, has NT in the middle and E with j at the ends: an NT dynamic type, so Gamma.
| Quadra | Rule | Four-letter codes | Types |
|---|---|---|---|
| Alpha | NT static, SF dynamic | ENTp, INTj, ESFj, ISFp | ILE, LII, ESE, SEI |
| Beta | ST static, NF dynamic | ESTp, ISTj, ENFj, INFp | SLE, LSI, EIE, IEI |
| Gamma | SF static, NT dynamic | ESFp, ISFj, ENTj, INTp | SEE, ESI, LIE, ILI |
| Delta | NF static, ST dynamic | ENFp, INFj, ESTj, ISTp | IEE, EII, LSE, SLI |
Quasi-quadras ignore the last letter. Each is three letters and their exact opposite, so ENT goes with ISF.
| Quasi-quadra | First three letters | Types |
|---|---|---|
| Phi | ENT or ISF | ILE, LIE, SEI, ESI |
| Psi | INT or ESF | LII, ILI, ESE, SEE |
| Omega | ENF or IST | EIE, IEE, LSI, SLI |
| Chi | INF or EST | IEI, EII, SLE, LSE |
Thinking forms cross static or dynamic with positivist or negativist. Positivist is a counting rule, explained in the next section.
| Thinking form | Rule | Four-letter codes | Types |
|---|---|---|---|
| Causal-deterministic | Static positivist | ENTp, ESFp, INFj, ISTj | ILE, SEE, EII, LSI |
| Holographic | Static negativist | INTj, ISFj, ENFp, ESTp | LII, ESI, IEE, SLE |
| Vortex | Dynamic positivist | ESFj, INFp, ENTj, ISTp | ESE, IEI, LIE, SLI |
| Dialectical-algorithmic | Dynamic negativist | ISFp, ENFj, INTp, ESTj | SEI, EIE, ILI, LSE |
All fifteen Reinin dichotomies
Every dichotomy is one, two, three or all four letters of the code. Four use a single letter, six use a pair, and five use a counting rule.
| Dichotomy | Letters | First pole | Second pole |
|---|---|---|---|
| Extraverted / Introverted | 1 | E | I |
| Intuitive / Sensing | 2 | N | S |
| Logical / Ethical | 3 | T | F |
| Rational / Irrational | 4 | j | p |
| Static / Dynamic | 1 and 4 | Ep or Ij | Ej or Ip |
| Democratic / Aristocratic | 2 and 3 | NT or SF | NF or ST |
| Carefree / Farsighted | 1 and 2 | EN or IS | IN or ES |
| Yielding / Obstinate | 1 and 3 | ET or IF | IT or EF |
| Constructivist / Emotivist | 3 and 4 | Tp or Fj | Tj or Fp |
| Tactical / Strategic | 2 and 4 | Np or Sj | Nj or Sp |
| Positivist / Negativist | 1, 2 and 3 | Odd count of E, N, T | Even count |
| Process / Result | 2, 3 and 4 | Even count of N, T, j | Odd count |
| Judicious / Decisive | 1, 2 and 4 | Even count of E, N, j | Odd count |
| Subjectivist / Objectivist | 1, 3 and 4 | Even count of E, T, j | Odd count |
| Asking / Declaring | All four | Odd count of E, N, T, j | Even count |
The counting rules sound fiddly but take seconds. For ESTj (LSE), the code holds E and T but not N, so the count of E, N and T is two. That is even, so LSE is a negativist. Of N, T and j it holds T and j, also two, so LSE is a process type.
The six pair rules line up with the six systems in the first table. Static and dynamic each take two temperaments. Democratic and aristocratic each take two clubs. The same goes for every pair. The full set of 35 systems builds the same structure from the dichotomy side.
Where four letters mislead
I still use three-letter codes for most things, and so does most of the community. The four-letter code has real costs.
- It looks backward compatible with MBTI, and it isn't. The function orders differ between the systems, so the same letters can describe a different type. The lowercase j and p are a warning, not a decoration.
- It hides the functions. LII tells you the type leads with logic and has intuition second. INTj makes you work that out. For anything about Model A, the three-letter code says it directly.
- Some groups don't show at all. Quadras, quasi-quadras and thinking forms need the whole code, as above.
So treat the four-letter code as a reading aid. It is the fastest way to sort a list of types into clubs, temperaments or dichotomy poles. For describing a type, the three-letter code is clearer.
Download the cheat sheet (PDF, 5 pages)
Further reading
- Small groups: every named system, with a page for each
- All 35 small-group systems: the same structure built from the dichotomies
- The sixteen types