Japan is the second-largest App Store market in the world by revenue. Japanese iPhone users have one of the highest average revenue per user (ARPU) figures of any country — consistently above the US in many app categories. The market is large, the users spend, and the iOS penetration rate is exceptional: Japan is one of the few major markets where iPhone has over 60% smartphone market share.
And yet, for the average indie developer, the Japan App Store might as well not exist. Their app is available there. The metadata is in English. The keyword field for the Japan locale is blank. Downloads from Japan are zero or near-zero, so the developer concludes there's no demand and moves on.
The demand is there. The opportunity is real. The metadata just isn't.
Why Japan Is Different From Every Other Market
Most large international App Store markets follow a predictable pattern: high English-language usage among tech-savvy users, partial keyword competition from localized apps, and a significant opportunity for properly localized metadata.
Japan doesn't follow that pattern. Japanese users predominantly search the App Store in Japanese — not in English, not in romanized Japanese, but in Japanese script (hiragana, katakana, and kanji). An app with English-only metadata is not just unoptimized for Japan; it's essentially absent from the search index for the searches Japanese users run.
This creates an unusually sharp divide:
- Apps with properly localized Japanese metadata rank and get downloaded
- Apps without it are virtually invisible to search
There's no middle ground where an English keyword vaguely matches a Japanese search. Either you've done the Japanese metadata or you haven't, and the ranking reflects that exactly.
The Revenue Case
Japan's App Store revenue figures are consistently striking. In a typical year, Japan accounts for roughly 10% of global App Store revenue — second only to the US, and comparable to or exceeding the entire European market combined.
For specific categories, the numbers are even more pronounced. Productivity apps, utility apps, health and fitness apps, and creative tools all perform strongly in Japan. Japanese users pay for apps; the culture of free-only usage that dominates some markets is less pronounced here.
Average revenue per download in Japan is among the highest in the world. In many categories, a Japanese user who finds and downloads your app is worth more in lifetime revenue than a US user, because Japanese users are more likely to pay for subscriptions and in-app purchases they find valuable.
What Japanese App Store Search Looks Like
Japanese users searching the App Store use a mix of scripts:
Hiragana and katakana for phonetic searches — these are the syllabic scripts used for everyday words and foreign loanwords. A user searching for a focus timer might type "フォーカスタイマー" (katakana transliteration of "focus timer") or "集中タイマー" (native Japanese — "concentration timer").
Kanji for concept-based searches — these are the character-based terms borrowed from Chinese that represent words and concepts. "習慣" (habit), "生産性" (productivity), "瞑想" (meditation).
Romaji occasionally — but less than you'd expect for app searches. Japanese users searching the App Store default to Japanese script for most category terms.
This means your Japanese keyword field needs actual Japanese keywords — not English terms, not romanized Japanese, not a machine translation of your English keywords. The vocabulary, the scripts, and the search intent need to come from Japanese user behavior data.
Common Japanese App Store Keyword Patterns
Some patterns worth understanding before you start research:
Loanword terms are common in tech categories. "アプリ" (apuri — "app"), "ノート" (nooto — "note"), "タスク" (tasuku — "task") are all katakana transliterations of English words that Japanese users search frequently. In many categories, the loanword version outperforms the native Japanese equivalent.
Function-first titles perform well. Japanese App Store culture favors clarity about what an app does over clever brand names. A title that clearly states the function in Japanese — even if it reads clinically — often outranks a brand-name title with a keyword in the subtitle.
Compound words matter. Japanese forms compound terms differently than English. What English speakers search as two separate words ("habit tracker") often appears as a compound in Japanese. Research should surface the actual compound forms users type, not just individual word translations.
Competitive gaps are large. For most categories outside of gaming and major social apps, the Japanese App Store has significantly fewer well-optimized apps than the US. Apps that have invested in proper Japanese metadata frequently rank in the top 10 for terms with meaningful search volume.
How to Approach Japanese Localization
Step 1: Keyword research in Japanese. Use AppTweak, ASOdesk, or AppFollow with the country set to Japan. Search your category in Japanese — if you don't speak Japanese, start with your core concept translated to Japanese and look at what the tool suggests. Focus on search volume scores and difficulty scores. Look at what your top Japanese-market competitors rank for.
Step 2: Native review of metadata. Machine translation produces Japanese that reads awkwardly to native speakers. Even if the keywords are technically correct, the title and description copy should be reviewed by a native speaker or a quality localization service. Poor Japanese copy doesn't destroy your keyword ranking, but it does hurt conversion — users who visit your listing and see stilted Japanese lose trust quickly.
Step 3: Localize the description. The description doesn't affect keyword ranking, but it does affect conversion. A Japanese user who finds your app via keyword ranking will read a description that should sound natural to them. Benefit framing that works in the US ("save time, get more done") may need cultural adaptation for Japan.
Step 4: Consider screenshot localization. Japanese users respond strongly to screenshots with Japanese text overlays. An English-language screenshot in a Japanese search result is a signal that the app may not be designed for them. Even simple text overlay translation on your first screenshot can improve conversion meaningfully.
Step 5: Fill every field. Title (30 chars), subtitle (30 chars), keyword field (100 chars), description. Every field contributes. The keyword field especially — for Japanese, where each character represents a full syllable or concept, 100 characters of Japanese keywords covers significant search surface area.
What to Expect After Localization
Timeline: Apple typically re-indexes metadata within 1–2 weeks of submission. Ranking movement for new keywords in a new locale often shows up within 2–4 weeks, sometimes faster.
For most apps entering the Japan market with proper metadata for the first time:
- Rankings appear for primary keywords within 2 weeks
- Organic downloads from Japan begin within 3–4 weeks
- Download volume grows over 2–3 months as behavioral signals accumulate (downloads → retention → ranking improvement)
The growth compounds. Once your app has initial rankings and Japanese users are downloading and keeping it, Apple's algorithm treats the behavioral signals as validation — which improves ranking further, which drives more downloads.
The Time Investment
Doing Japanese keyword research properly takes 5–8 hours — more than most markets because of the script complexity and the need to verify terms across multiple Japanese search behavior sources. Writing and reviewing localized copy adds more time.
For an indie developer with an app to build and support, that's a significant time investment for one market. Which is why most never do it — and why the competitive gap remains so large.
LocalizeRank includes Japan in every plan. Per-market keyword research, competitor gap analysis, and a ready-to-paste Google Sheet covering title, subtitle, keyword field, and description for the Japan locale — along with 4 other high-ROI markets in the Starter plan. Starting at $49.
The Japanese market doesn't require a large app company or a localization agency budget. It requires the right keywords in the right fields, researched from actual Japanese App Store data.