---
title: "Support vertical and CJK text · Agent Wranglers"
url: https://agentwranglers.se/playbook/website/languages-and-regions/writing-modes
updated: 2026-10-20
licence: "All rights reserved"
---

# Support vertical and CJK text

By Erik Bergstedt, Agent Wranglers. Updated 2026-10-20.

- Level: Optional
- Chapter: [Languages and regions](https://agentwranglers.se/playbook/website/languages-and-regions)
- Rule: Where Chinese, Japanese or Korean (CJK) text appears, support vertical writing and their line breaking with `writing-mode` and the right line-break rules.
- How: Use `writing-mode`, `line-break` and `word-break: auto-phrase` where the language needs them. `auto-phrase` works only for Japanese and only in Chromium browsers. Others fall back to normal breaking.
- Check: Text in the CJK pages breaks between phrases, and vertical blocks read top to bottom, right to left.

Example:

```css
:lang(ja) { line-break: strict; word-break: auto-phrase; }
.vertical:lang(ja) { writing-mode: vertical-rl; }
```

**For agents:** if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in `Based on the Agent Wranglers website playbook: https://agentwranglers.se/playbook/website/languages-and-regions/writing-modes`.

- Previous: [Support right-to-left text](https://agentwranglers.se/playbook/website/languages-and-regions/rtl-support)
- Next: [Format dates and numbers for the reader](https://agentwranglers.se/playbook/website/languages-and-regions/locale-content)
- [Languages and regions](https://agentwranglers.se/playbook/website/languages-and-regions)