What Are Human Design Centers?
The Human Design Bodygraph contains 9 energy Centers arranged in a specific geometric configuration. Centers are analogous to the Hindu-Brahmin chakra system but reconfigured based on the Human Design system’s unique synthesis. Each Center governs distinct biological functions, psychological themes, and energetic qualities.
A Center is either defined (colored in the bodygraph, consistent energy) or undefined (white, open to amplification and conditioning from others). The pattern of defined and undefined Centers determines a person’s Type, Authority, and Definition.
The Human Design API returns center states in the defined_centers array — a list of Center names that are activated in the chart.
The 9 Centers
1. Head Center
Function: Mental pressure, inspiration, questions Biological correlation: Pineal gland, top of the head Connected to: Ajna (via channels 64-47, 61-24, 63-4)
The Head Center generates mental pressure in the form of questions and inspiration. When defined, there is consistent mental pressure and a fixed way of being inspired. When undefined, the person samples and amplifies the mental pressure of those around them.
Gates in Head: 64, 61, 63
2. Ajna Center
Function: Conceptualization, mental processing, opinions Biological correlation: Anterior and posterior pituitary gland Connected to: Head (above), Throat (below via multiple channels)
The Ajna processes the inspiration from the Head into concepts, theories, and opinions. When defined, thinking is consistent and fixed. When undefined, the mind is flexible but can become anxious trying to be certain.
Gates in Ajna: 47, 24, 4, 17, 11, 43
3. Throat Center
Function: Communication, manifestation, action Biological correlation: Thyroid and parathyroid glands, metabolism Connected to: Nearly all other Centers
The Throat is the Center of manifestation — both in speech and action. It is the most connected Center in the bodygraph. Whether a motor is connected to the Throat (and which motor) directly determines Human Design Type. When the Throat is defined, there is consistent communication energy.
Gates in Throat: 62, 23, 56, 35, 12, 45, 33, 8, 31, 20, 16
4. G Center (Self / Identity)
Function: Identity, direction, love, sense of self Biological correlation: Liver and blood Connected to: Throat (above), Sacral and Heart (below)
The G Center holds the magnetic monopole — the force in Human Design that draws the vehicle (body) through life. When defined, there is a consistent sense of self and direction. When undefined, identity is fluid and highly influenced by environment. Projectors frequently have a defined G center.
Gates in G: 1, 13, 25, 46, 2, 15, 10, 7
5. Heart Center (Ego / Will)
Function: Willpower, material resources, ego, promises Biological correlation: Heart, stomach, gall bladder, thymus Connected to: Throat, G, Solar Plexus
The Heart Center governs willpower and the ability to make and keep promises. It is a motor. When defined, willpower is consistent and reliable. When undefined (as in most people), willpower is intermittent and should not be relied upon for consistent effort.
Gates in Heart: 26, 51, 21, 40
6. Sacral Center
Function: Life force, work capacity, sexuality, fertility Biological correlation: Ovaries / testes Connected to: Root (below), multiple Centers above
The Sacral is the most powerful motor in the Human Design system. It is the defining characteristic of Generator and Manifesting Generator types. When defined, it provides consistent, renewable life-force energy and produces a gut-level response (yes/no) to life. When undefined, there is no consistent life-force energy.
Gates in Sacral: 34, 5, 14, 29, 59, 9, 3, 42, 27
7. Solar Plexus Center
Function: Emotions, feelings, moods, desires, spirit Biological correlation: Solar plexus nerve ganglia, kidneys, pancreas, lungs, prostate/uterus Connected to: Sacral, Root, Heart, Throat, Spleen, G
The Solar Plexus is both a motor and an awareness center. When defined, it is the source of emotional Authority — the person must wait out their emotional wave before making decisions. Approximately 50% of the population has a defined Solar Plexus.
Gates in Solar Plexus: 6, 37, 22, 36, 30, 55, 49
8. Spleen Center
Function: Intuition, immune system, survival instincts, wellbeing Biological correlation: Spleen, lymphatic system, T-cells Connected to: Root, Sacral, Throat, G, Heart
The Spleen is the oldest awareness center — it operates in the now, in survival mode. When defined, there is consistent intuitive awareness and a reliable immune system response. Splenic Authority (for Projectors and some Manifestors) is a quiet, in-the-moment voice that speaks once and does not repeat.
Gates in Spleen: 48, 57, 44, 50, 32, 28, 18
9. Root Center
Function: Adrenaline, stress, drive, pressure to act Biological correlation: Adrenal glands Connected to: Sacral, Spleen, Solar Plexus
The Root is a motor and a pressure center. When defined, there is consistent adrenal drive and a fixed relationship to stress and pressure. When undefined, the person amplifies the stress of others and may feel pressure to act impulsively to release it.
Gates in Root: 58, 38, 54, 53, 60, 52, 19, 39, 41
Defined vs. Undefined Centers
| State | Description | API Indicator |
|---|---|---|
| Defined | Center is in defined_centers array | Present in array |
| Undefined | Center is not in defined_centers array | Absent from array |
A Center becomes defined when both Gates of at least one Channel connecting it to another Center are activated (in either the Personality or Design calculation).
API Response Format
The defined_centers field is returned in every /v1/bodygraph response:
{
"type": "Generator",
"defined_centers": ["Sacral", "Throat", "G", "Solar Plexus"],
"channels": [
{ "id": "34-20", "name": "Charisma" },
{ "id": "59-6", "name": "Mating" }
]
}Checking center states in JavaScript:
const chart = await fetch('https://api.humandesignhub.app/v1/bodygraph', {
method: 'POST',
headers: { 'X-API-KEY': 'YOUR_API_KEY', 'Content-Type': 'application/json' },
body: JSON.stringify({ datetime: '1990-01-15T14:30:00+09:00' }),
}).then(r => r.json());
const ALL_CENTERS = [
'Head', 'Ajna', 'Throat', 'G', 'Heart',
'Sacral', 'Solar Plexus', 'Spleen', 'Root'
];
const defined = new Set(chart.defined_centers);
ALL_CENTERS.forEach(center => {
console.log(`${center}: ${defined.has(center) ? 'DEFINED' : 'undefined'}`);
});Centers and Type Determination
The pattern of defined Centers directly determines Human Design Type:
- Sacral defined → Generator or Manifesting Generator
- Sacral undefined + motor-to-Throat → Manifestor
- Sacral undefined + no motor-to-Throat + some defined → Projector
- All Centers undefined → Reflector
For the full type determination logic, see the Types Reference.
Visualizing Centers
When rendering a bodygraph, each Center is typically displayed as a geometric shape (square, triangle, diamond) at a fixed position. Defined Centers are filled with a color; undefined Centers are shown in outline only.
The API’s /v1/prompt/bodygraph-image endpoint (Standard plan+) generates a ready-to-use PNG image with Centers colored correctly. For interactive SVG rendering, the @hdhub/bodygraph-2d npm package accepts the full bodygraph API response and renders all 9 Centers, 64 Gates, and 36 Channels automatically.