Japanese App Store Localization: Storefronts and Keyword Bytes

Japan's row is the only row that names Japanese, and it is also one of two rows that name English (U.S.) (the other is the United States). So the whole 100-byte field is about one market. The Japan row is the one to check on the Japan keyword page.

The table lists English (U.S.) as the additional language there, not English (U.K.) as in most rows; see English (U.S.). The locale code Apple gives is ja.

• Default language in 1: Japan.
• Additional language in none.

Every default storefront also lists another language (English (US)), so Japanese is never the only localization there.

Apple's keyword reference allows 100 bytes, not 100 characters. Counted as UTF-8, the example below contains 28 three-byte characters (separators excluded). At three bytes a character the field holds at most 33 characters of keywords, commas included. The words below are a hypothetical keyword list for a habit tracker called Streakly; they are illustrations, not validated search terms, and each has at least three characters.

Joined with commas and no spaces after them, the field is:

習慣化,習慣トラッカー,目標管理,リマインダー,毎日記録,三日坊主

That is 33 characters and 89 bytes: 84 bytes of keywords plus 5 commas, leaving 11 of the 100 bytes free. The byte counts assume UTF-8; confirm the final count in App Store Connect before you save.

Japanese mixes kanji, hiragana and katakana. Every one of them takes three bytes per character, so 習慣トラッカー costs 21 bytes while an English phrase of the same meaning, habit tracker, costs 13. Katakana loanwords like リマインダー are long in characters, which makes them expensive.

Apple does not document whether a word in hiragana, katakana and kanji matches searches in the other forms, so a spelling variation is a test, not a given. Every keyword must also be longer than two characters: 習慣 on its own is two characters and fails, while 習慣化 passes. Compare Chinese (Simplified) and Korean, which face the same three-byte cost.

LocalASO checks keywords in 52 App Store storefronts, each in the storefront's local language, so you can compare your Japanese candidates with the English ones in one place. Keywords, ranks and listings stay in a database on your Mac. LocalASO is a one-time $29 purchase and the app needs a license key to run; the setup is in the localization docs and the price is on the pricing page. To test the field you just built, use the keyword field checker, or browse every language page. See also: Chinese (Simplified), Chinese (Traditional), Korean, English (U.S.).