> ## Documentation Index
> Fetch the complete documentation index at: https://mehen.ophi.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# JTF rule conformance

> Japan Translation Federation's 12 rules, mechanically checkable on Markdown blocks.

The Japan Translation Federation's **JTF Japanese Style Guide for Translators** has 12 mechanical rules
that mehen checks on Japanese-tagged Markdown blocks.

## Rules

| #  | Check                                                                          | Severity |
| -- | ------------------------------------------------------------------------------ | -------- |
| 1  | keitai/jōtai consistency (`である` / `です・ます`)                                     | warn     |
| 2  | `、` / `。` used as punctuation                                                  | info     |
| 3  | Stick to Jōyō kanji (flag `hyōgai`)                                            | warn     |
| 4  | Okurigana per official rules                                                   | info     |
| 5  | Trailing long-vowel mark on katakana compound endings (`コンピューター` not `コンピュータ`) | warn     |
| 6  | Long katakana compounds broken with `・` or half-width space                    | info     |
| 7  | Kanji / hiragana / katakana full-width                                         | error    |
| 8  | Digits and Latin alphabet half-width                                           | warn     |
| 9  | Symbols full-width                                                             | info     |
| 10 | No space between full-width and half-width                                     | info     |
| 11 | `.`, `,`, spaces half-width                                                    | info     |
| 12 | Standardize unit notation                                                      | info     |

## How violations surface

Each violation contributes to:

* The document's **`jtf_violation_density`** (input to Japanese WQS).
* A list of `(line, column, rule, message)` flags reported in the JSON output.
* Per-rule callouts in the [PR comment](/guides/pr-comment-design).

## References

* Japan Translation Federation: [Japanese Style Guide for Translators (3rd Edition)](https://www.jtf.jp/jp/style_guide/styleguide.html).

## See also

* [Japanese script composition](/metrics/markdown/prose/japanese-script-composition) — Tier 0 inputs.
* [textlint-ja subset](/metrics/markdown/prose/textlint-ja) — additional Japanese rules.