# Subrealms

Child names claimed under a parent Realm's rules, how the parent controls them, and what a claimant must satisfy.

Page ID: protocol/realms/subrealms
Applicability: protocol-behavior
Authority: reference-implementation
Networks: mainnet
Verified: 2026-09-01
Locale: en
URL: https://bitcoinuniverseio.github.io/atomicals-and-arc-20/protocol/realms/subrealms/

---
A Subrealm is a name under a parent Realm. The parent defines the rules; anyone who satisfies them
can claim a Subrealm.

## The parent controls the rules

Reference commands: `enable-subrealms`, `disable-subrealms`, `pending-subrealms`,
`mint-subrealm <realm>`, `summary-subrealms`. See the [CLI reference](/reference/cli/).

A parent can:

- enable or disable Subrealm claiming;
- define rules that a claim must satisfy;
- require a payment to a specified output;
- leave claiming open, subject only to name availability.

## Claiming

1. Read the parent's current rules, at a specific height.
2. Build a claim that satisfies them, including any payment.
3. Mint with `mint-subrealm`.
4. Wait for confirmation, then for resolution.
5. Confirm you are the verified winner, not a losing candidate.

A claim that misses a rule still produces a confirmed Bitcoin transaction and costs a fee.

## Payments

Where a rule requires payment, the payment output and its marker are part of validity. A payment
marker output identifies which claim the payment belongs to, so a validator can match them.

Paying the right amount to the wrong script, or omitting the marker, makes the claim invalid.

### A payment is never satisfied in a split transaction

A payment carried in a transaction that also carries a split (`y`) operation is refused, even when
the amount and the marker are both correct. The reason is that a split can reassign ARC-20 value
inside the very transaction that is meant to pay, so the payment cannot be judged in isolation.

This is the indexer being conservative rather than a rule stated in the format, and it may refuse a
payment another implementation would accept. Send the payment as its own transaction. Combining it
with a token movement to save a fee costs the claim.

## Pending claims

A parent can inspect outstanding claims with `pending-subrealms`. A product showing Subrealms
should distinguish:

| State | Meaning |
| --- | --- |
| Pending | A claim exists and has not resolved |
| Verified winner | The rules awarded the name |
| Losing candidate | Another claim won |
| Rejected | A rule was not satisfied |

Showing a pending claim as owned is the failure to avoid.

## Hierarchy

Subrealms can nest. A hierarchy read should return the root, the path, and the direct children,
and should say when the child list was truncated rather than silently cutting it.

The Universe read model exposes hierarchy and direct Subrealm listing with an explicit truncation
flag. See [NFT and Realm API](/reference/api/atomicals-nfts-realms/).