# Page Not Found

The URL `files/09t9uNOq6LdOKyW4q3MZ` does not exist. This page may have been moved, renamed, or deleted.

## Suggested Pages

You may be looking for one of the following:
- [唯一矩形（UR）](https://sudoku.kazusa.tech/full-marking-techniques/04-unique-rectangle.md)
- [欠一数组（ALC）](https://sudoku.kazusa.tech/full-marking-techniques/09-almost-locked-candidates.md)
- [唯一环（UL）](https://sudoku.kazusa.tech/full-marking-techniques/06-unique-loop.md)
- [双强链](https://sudoku.kazusa.tech/chain-theory/01-two-strong-link-chain.md)
- [弱区域和删数的秩](https://sudoku.kazusa.tech/rank-theory/08-rank-of-link-and-elimination.md)

## How to find the correct page

If the exact page cannot be found, you can still retrieve the information using the documentation query interface.

### Option 1 — Ask a question (recommended)

Perform an HTTP GET request on the documentation index with the `ask` parameter:

```
GET https://sudoku.kazusa.tech/full-marking-techniques/04-unique-rectangle.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

### Option 2 — Browse the documentation index

Full index: https://sudoku.kazusa.tech/sitemap.md

Use this to discover valid page paths or navigate the documentation structure.

### Option 3 — Retrieve the full documentation corpus

Full export: https://sudoku.kazusa.tech/llms-full.txt

Use this to access all content at once and perform your own parsing or retrieval. It will be more expensive.

## Tips for requesting documentation

Prefer `.md` URLs for structured content, append `.md` to URLs (e.g., `/full-marking-techniques/04-unique-rectangle.md`).

You may also use `Accept: text/markdown` header for content negotiation.