English to Japanese: what actually changes in your game text

If you have only ever shipped in English, Japanese is often the first language that breaks assumptions baked into your UI and your text pipeline. Not because Japanese is exotic, but because English hides a lot of decisions that Japanese forces you to make explicitly — and because Japanese text behaves differently on screen in ways a developer who cannot read it can still catch, if they know what to look for.

Three scripts, one line of text

Japanese text routinely mixes three writing systems in a single sentence: kanji (logographic characters, mostly borrowed from Chinese, used for nouns and word stems), hiragana (a phonetic syllabary used for grammatical particles, inflections, and native words), and katakana (a second phonetic syllabary, used mainly for loanwords, foreign names, and emphasis, similar in role to italics in English). A single line of dialogue might use all three plus Latin letters and Arabic numerals for a brand name or a stat.

This is normal Japanese, not a translator's inconsistency. If your QA process flags 'mixed scripts' as a defect the way it might flag mixed fonts in English, you will generate false positives on every line.

No spaces between words

Japanese does not separate words with spaces. Line breaking therefore cannot use the 'break at the nearest space' logic that works for English — a naive line-wrap algorithm will happily break in the middle of a word or, worse, right before a closing punctuation mark, which is disallowed by Japanese typographic convention (kinsoku shori: certain characters like closing brackets, 、and 。must never start a line, and certain characters like opening brackets must never end one). If your renderer wraps on whitespace only, Japanese text will visibly break in the wrong places.

Shorter in characters, wider per glyph

Japanese text is frequently shorter than English in character count for the same meaning, because a single kanji can carry what takes an English word or phrase to say. Teams sometimes assume this means Japanese needs less UI space than English. It usually does not, because each Japanese character occupies roughly a full-width square glyph cell — noticeably wider than a Latin letter — so the character-count savings and the per-character width increase partially cancel out. Measure actual rendered width, not character count, before deciding a Japanese string will fit.

Vertical text and font requirements

Japanese can be set horizontally or vertically (top-to-bottom, columns running right to left) — vertical setting is common in narrative and dialogue-heavy contexts, less so in UI. If your game supports vertical text at all, punctuation, brackets, and small kana all need to rotate or reposition correctly, which most Latin-script fonts and text engines were never built to do.

A font that renders English correctly may have no Japanese glyphs at all, or an incomplete set — kanji coverage in particular varies enormously between fonts, and a font missing a character will show a fallback box (tofu) or silently substitute a system font with a different weight and metrics. Confirm full glyph coverage for your actual script content, not just a handful of test characters.

Punctuation width and half-width vs. full-width

Japanese punctuation marks (、。「」！？) are typically full-width, occupying the same square cell as a kanji, and this is a deliberate typographic convention, not a formatting error. Mixing in half-width Latin punctuation (a straight ASCII comma or an ASCII exclamation mark) inside Japanese prose reads as visibly wrong to a native reader, the way a missing space after a period reads as wrong in English. Numerals and Latin abbreviations are more often kept half-width even within Japanese sentences, so the convention is script-dependent, not uniform.

Furigana and the register decisions English does not force

Furigana are small hiragana printed above (or beside, in vertical text) a kanji to show its reading — used for uncommon kanji, character names, or to make text accessible to younger players. If your target audience includes children or your kanji usage is heavy, deciding where furigana is needed is a real localization decision, not a nice-to-have, and it needs layout space your English source never accounted for.

Japanese also forces choices English text can leave implicit: which of several first-person pronouns a character uses, and what politeness level (from casual speech to formal keigo) they speak at, both of which signal age, gender, social status, and relationship in ways a single neutral English 'I' and a flat tone do not. A translator has to make these calls per character even when the English source gives no explicit cue.

Practical checks for a developer who cannot read Japanese

You do not need to read Japanese to catch most integration problems. Watch for these:

• Tofu boxes or obviously mismatched font weight — usually missing glyph coverage
• A closing bracket, 、or 。 sitting alone at the start of a line — a kinsoku shori violation
• ASCII commas, periods, or exclamation marks inside otherwise full-width text — check with a native reader, since some numerals/abbreviations are legitimately half-width
• Text visibly overflowing or clipped even though the character count looked short in your source string table
• The same UI button rendering at a very different width across locales for what should be a short label