A monolingual team can ship for years without hitting the bugs that lose them Japanese users on day one. I kept finding the same five gaps while looking at foreign dev-tools, so I turned the check into a CLI. Run it npx github:greymoth-jp/jp-ready-check your-site.com No install, no account. It fetches the page once and scores it 0–5. What it checks hreflang ja — without it, Google.co.jp / Yahoo! Japan can't reliably surface your Japanese pages....