This is the most expensive Japan gap I find, because the work is already paid for. A team translates the UI, ships ja.json, and assumes Japan is handled. Then no Japanese user ever sees it, because translating the app and being discoverable in Japan are two completely different jobs. I'm a Tokyo-native builder; here's exactly why a shipped locale file does nothing for discovery, and the three things that actually make your Japanese reachable.
A ja.json / ja.yml translates strings for a user who is already inside your app, usually after they've switched a language setting. That's the last 5% of the journey. The other 95% — a Japanese person searching in Japanese, landing on a page, and deciding you're worth trying — happens before they ever reach the app, and the locale file touches none of it.
This is the trap. The team sees Japanese rendering in the product and concludes "Japan is done." But the marketing site, the docs, and the search presence that decide whether a Japanese user arrives are still English-only. The translation is real and invisible at the same time.
1. A real, crawlable Japanese URL. A Japanese page needs its own address — a /ja route or a ja. subdomain that serves Japanese HTML on first load. A client-side language toggle that swaps text after the page renders is not enough: there's no distinct URL for Google to index, so there's nothing to rank. The Japanese version has to exist as a page, not a state.
2. hreflang annotations. Add reciprocal <link rel="alternate" hreflang="ja" href="…/ja"> (and the matching hreflang="en" back) so google.co.jp knows the Japanese version exists and serves it to Japanese searchers instead of your English page. Without it, even a perfect Japanese page can be passed over for the English one.
3. Pages that target Japanese queries. Your English pages will never rank for 「(category) 比較」 or 「(category) おすすめ」. You need Japanese pages written around the terms a Japanese buyer actually types — comparison, alternative-to, and use-case queries in Japanese. This is content work, not a translation of your English SEO.
A Japanese team evaluating your category searches in Japanese first. If you have no indexed Japanese pages, you don't appear — and a domestic competitor that did publish Japanese pages gets shortlisted before you're ever compared on the merits. You don't lose on features; you lose by being absent at the moment the decision starts.
The cruel part: this happens to teams whose product is better and who already translated it. The locale work that should have been an advantage sits unused while a weaker, louder local option wins the search.
If you already have a translated app, the highest-leverage first move is usually a single real Japanese landing page at /ja — server-rendered, hreflang-paired with its English twin, written around your top one or two Japanese buyer queries. It surfaces the localization you already paid for and gives Google something to index. From there you expand to docs and category pages. You don't need a full Japanese site on day one; you need to stop hiding the Japanese you already have.
Surfacing an existing translation is the cheapest big win in Japan-readiness — but only if it's actually your bottleneck and not a missing 特商法 page or USD-only billing. A glovrex Japan-readiness audit checks all five signals against your live site and tells you what to fix first. You can also see how 17 real foreign dev tools score — many of them ship Japanese and route none of it.
General guidance for foreign software teams, written 2026-06 by a Tokyo-native builder. Implementation specifics (framework routing, hreflang placement) depend on your stack. Corrections welcome: hello@glovrex.com.