Translate a .NET app into Japanese

What changes when a .NET app goes Japanese

Japanese has a single CLDR plural category, other. If your code picks between FileCount_One and FileCount_Other, both keys get the same text, such as {0} 件のファイル. The logic still works; it simply has nothing to choose between.

Word order is the bigger change. {0} of {1} naturally becomes {1} 件中 {0} 件. Indexed String.Format placeholders let the translation move them without touching your code, provided the whole sentence lives in one value. The classic trap is concatenation, for example "Delete " + name + "?": no translation can move the verb to the end of a Japanese sentence. Turn these into single strings with placeholders before you send the files.

Composite formats such as {0:N0} or {0:d} are kept as they are; the ja-JP culture at runtime will produce Japanese dates and digit grouping.

Script, fonts and layout

A Japanese interface mixes kanji, hiragana and katakana with no spaces between words. A label often has fewer characters than its source, but each glyph is wider and taller, so a pixel-tight WinForms button may clip キャンセル or cut a kanji in half.

• Fonts: if a form forces a typeface without Japanese glyphs, some machines will show empty boxes. Plan a Japanese UI font (for instance Yu Gothic UI or Meiryo UI) for the ja culture, whether in WinForms, WPF or MAUI.
• Line breaks: without spaces, text wraps between characters, but never before 。, 、 or a small kana. Let controls grow rather than fixing widths.
• Punctuation: Japanese uses full-width 、 and 。; digits stay half-width, and half-width katakana looks dated in a modern UI.
• Access keys: the Japanese convention puts the mnemonic in brackets, 保存(&S) for &Save. Check these labels after translation.

Register and Japanese conventions

In business software, messages to the user use the polite -masu form: File saved. becomes ファイルを保存しました。, not the plain 保存した. Buttons and menu items stay short nouns: 保存, 設定, 削除. A confirmation reads naturally as 削除してもよろしいですか？.

Many technical terms are written in katakana (ログイン, ダウンロード); consistency matters more than the choice itself. Use the resource comment to say when a term must stay in Latin script, such as a product name.

For formats, ja-JP shows dates as yyyy/MM/dd and the yen has no decimal places. If a string hard-codes $0.00 or MM/dd/yyyy, the code should rely on the culture instead: date formats are not translated.

What Manuce returns, and what it does not do

In a .resx file, Manuce translates the data/value elements and reads comments as context: a comment such as “button, 6 characters max” steers the choice towards 保存 rather than a sentence. Non-text resources in a localisable WinForms form (sizes, locations, images) stay intact.

• The returned file is the same file: indentation, key order, quotes, comments, line endings, encoding and BOM are preserved; only the values change.
• Each translated value is checked against the source: if {0} or a tag goes missing in the Japanese and the mismatch persists, the source value is kept and the report says so.
• Not translated: keys, empty values, URLs, email addresses, numbers, colours, date formats, identifiers and anything marked as non-translatable.

Manuce does not rename the file, build the satellite assembly, resize your controls or fix concatenation in code. Pricing is based on the words in the values, keys and tags excluded, with the ×1.6 coefficient that applies to Japanese.

Preparing and checking

1. Merge concatenated fragments in code into full strings with {0}, {1}.
2. Comment ambiguous resources: is “Open” a button verb or a status? In Japanese, 開く and オープン are not interchangeable.
3. Mark product names and codes that must not change as non-translatable.
4. On return, name the file Resources.ja.resx (or ja-JP), run the app under the Japanese culture and walk through every screen: clipping, font, (&S) access keys.
5. Read the report: every value left in the source language is explained.

Before paying, the free sample translates one paragraph of your file at the chosen level, so you can judge the polite register on your own labels.

In practice

1. Replace concatenation in code with full strings using placeholders.
2. Upload your .resx files and review the quote and free sample.
3. Download the translated file and name it Resources.ja.resx.
4. Test the UI under the ja-JP culture and read the report.