Queried by: developersanalyticsvalidators
The Big Picture
Only keeps last BlockHashCount hashes. For older history, use archive nodes.
Use Cases
- Verify transactions in specific blocks
- Build historical proofs
From Chain Metadata
Map of block numbers to block hashes.
Purpose & Usage
Purpose
Historical block lookup within retention window.
Common Query Patterns
- Query hash by block number
- Verify block inclusion
Query Keys
| # | Name | Type | Description |
|---|---|---|---|
| 1 | key1 → block_number | u32 | Block number |
Stored Value
32-byte block hash
Code Examples
import { ApiPromise, WsProvider } from "@polkadot/api";
import { stringCamelCase } from "@polkadot/util";
const provider = new WsProvider("wss://entrypoint-finney.opentensor.ai:443");
const api = await ApiPromise.create({ provider });
// Query BlockHash storage
const key1 = 0;
const result = await api.query
[stringCamelCase("System")]
[stringCamelCase("BlockHash")](
key1
);
console.log("BlockHash:", result.toHuman());Runtime Info
- Pallet
- System
- Storage Kind
- Map
- First Version
- v101
- Current Version
- v393