# I Ching Hexagram Relations API (Nuclear, Inverse, Opposite)

> I Ching Hexagram Relations API (Nuclear, Inverse, Opposite) is a paid API for AI agents from api.cn402.com, paid per call via x402, $0.08/call, status unknown (last checked 2026-09-14).

Returns the three derived hexagrams — nuclear (互卦), inverse (综卦), and opposite (错卦) — for a given I Ching hexagram

## Facts

- Endpoint: GET https://api.cn402.com/iching/relations
- Price: $0.08/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-cn402-com-b5a00880
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XsetUfZyFdmp62AqeI5Iz

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability api-cn402-com-b5a00880
```

Example prompt: What are the nuclear hexagram, inverse hexagram, and opposite hexagram for I Ching hexagram number 30 (Li / Fire)?

## When to prefer this

Use this endpoint when you need specifically the three classical I Ching transformation relations (nuclear, inverse, opposite) for a single hexagram, and do not need a full reading or interpretation. Prefer the sibling 'complete I Ching analysis' endpoint if you also need changing lines, judgment text, or image text. This endpoint is ideal for lightweight transformation lookups in divination workflows or educational applications about hexagram structure.

## Known failure modes

- Invalid hexagram number (outside 1-64 range) returns an error
- Missing required hexagram input parameter returns 400-level error
- Payment not provided or insufficient USDC results in 402 Payment Required
- Malformed request body returns parsing error

## How this service works

Hexagram relations, 互卦 综卦 错卦, nuclear hexagram, inverse hexagram, opposite hexagram, I Ching transformation analysis, hexagram derived gua. For a given hexagram return its nuclear (互卦), inverse (综卦), and opposite (错卦) related hexagrams.

## Output

Returns the three derived hexagrams related to the input hexagram: the nuclear hexagram (互卦, formed from inner lines 2-5), the inverse hexagram (综卦, lines flipped upside-down), and the opposite hexagram (错卦, all lines reversed yin/yang), each with their number and name.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "num": {
   "type": "string",
   "description": "Num (required)"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-cn402-com-b5a00880/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.cn402.com](https://www.zero.xyz/host/api.cn402.com/llms.txt)