A primary way that relationships between Enneagram types are explored is through the use of triads.

**Enneagram triads involve grouping the nine personality types into three groups of three. All three types in a group share something in common. The centers of intelligence are the best known triads.**

Even though "the centers" are sometimes simply called "the triads" by some, they're only one of four possible triadic groupings of the Enneagram types. Other sets of triads besides the centers are referred to as stances, object relations groups, harmonics, harmony triads, Hornevian groups, and more.

Triadic groupings generally organize around types 3, 6, and 9 as indicated by the triangle on the Enneagram symbol.

### The 1st Triads

Starting with 3, 6, and 9, the three points from the triangle on the Enneagram symbol, the 1st triads are formed by looking one number to the right and one number to the left.

- 891
- 234
- 567

This 1st set of triads are generally called the centers of intelligence or simply the centers. Most Enneagram authors and teachers teach the centers as a crucial part of the Enneagram types.

Click here to learn more about the centers.

### The 2nd Triads

Starting with 3, 6, and 9 again, the 2nd triads are formed by looking two numbers to the right and two to the left.

- 135
- 468
- 792

The 2nd set of triads are not commonly used. One interpretation of the 2nd triads calls them Harmonic Groups where

- 135 are in the Competency Group
- 468 are in the Reactive Group
- 792 are in the Positive Outlook Group

The Harmonic Groups are a product of the Enneagram Institute and can be found in the book The Wisdom of the Enneagram.

### The 3rd Triads

When we look three to the right and three to the left of 3, 6, or 9 we simply end up with a triad consisting of 3, 6, and 9. Because of this the 3rd triads, unlike the 1st, 2nd, and 4th triads, don't center around 3, 6, and 9.

- 147
- 258
- 369

The 3rd set of triads aren't commonly used either. There are two interpretations you may run across.

One interpretation of the 3rd triads originated from the Enneagram Institute called the Object Relations Groups where types

- 147 are in the Frustration Group
- 258 are in the Rejection Group
- 369 are in the Attachment Group

A second interpretation of the 3rd triads is called the Harmony Triads where types

- 147 are Idealists
- 258 are Relationists
- 369 are Pragmatists

### The 4th Triads

The 4th triads again start with 3, 6, and 9 but looks four to the right and four to the left.

- 738
- 162
- 495

The 4th set of triads are commonly used but not as much as the centers (1st triads). This set of triads is generally interpreted through Karen Horney's neurotic trends and associated types.

- moving against people - the aggressive types
- moving toward people - the compliant types
- moving away from people - the detached or withdrawn types