Japan Internationalization

Overview

Designing for the Japanese market involves more than just translating text — it requires thoughtful localization that respects cultural norms, language structure, visual preferences, and platform-specific expectations. Japanese internationalization encompasses adjustments in typography, date and currency formatting, layout, hierarchy, and interaction patterns to ensure that products feel natural and intuitive to Japanese users.

Adapting visual, typographic, and structural norms demonstrates cultural fluency and reassures Japanese users that Amex understands and respects their expectations.

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Designing with Japanese Fonts

Characters

Japanese text is a blend of characters from four different writing systems – hiragana, katakana, Latin alphabet and kanji, often in the same sentence.​

• Kanji, combine to represent most objects, ideas, and actions
• Hiragana, links and conjugates kanji and adds grammatical nuance
• Katakana, represents non-Japanese proper nouns, and concepts

Japanese characters are typically full-width and designed to “float” in the optical center of a square of negative space. Each glyph occupies a fixed 1 em square, so height = width.​

Latin glyphs of varying widths sit on a common baseline, with ascenders and descenders reaching beyond the x-height, in contrast to the uniform square grid within Japanese type. When combined with Japanese, Latin characters appear too small and sitting too high or too low compared to their Japanese counterparts.​

Font Stack

Use a font stack that prioritizes a Japanese or CJK font like Hiragino Kaku Gothic ProN, Yu Gothic UI, and Noto Sans JP before Latin only fonts like SF Pro or Roboto.​

System fonts like San Francisco for iOS/macOS  does not include native Japanese glyphs by default. On Apple devices, the system silently falls back to Japanese fonts like Hiragino Sans for Japanese text, which can lead to visual inconsistencies in height.

Platform	Default JP System Font	Notes
iOS/macOS	San Francisco + Hiragino Sans	SF Pro is first, Hiragino fills missing CJK
Android	Roboto + Noto Sans CJK JP	Roboto first, then Noto Sans for Japanese
Web (Windows)	Yu Gothic UI	For Japanese UI; older: MS PGothic

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Type Hierarchy

Clear typographic hierarchy is essential in Japanese design to help users quickly understand and navigate content. Just like in Latin-based languages, visual hierarchy should mirror the content structure, making it easier for both users and search engines to recognize the main topics of a page. Proper use of HTML heading tags—such as assigning the page title as an <h1>, subtitles as <h2>, and so on—is crucial. This not only improves SEO but also ensures that assistive technologies, like screen readers, can accurately communicate the page structure to users with visual impairments.

Title text should be bold and noticeably larger than body text, helping users quickly orient themselves when scanning or skimming a page. In Japanese text, where dense characters can make content feel visually uniform, it’s even more important that headings stand out. Consistent and intentional hierarchy improves readability, accessibility, and overall user experience for Japanese audiences.

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Text Formatting

Line Height & Line Length for Body Text

Japanese text tends to be 20–55% longer than English due to the nature of the language—complex kanji, kana, and the absence of spaces between words. This creates a denser visual texture compared to Latin-based languages. To maintain readability, it’s important to apply slightly looser line spacing, which gives each character’s shape and outline more breathing room and reduces visual fatigue, especially in longer content. Set a minimum line height of 1.5 (150%) for Japanese body text. This allows the text to breathe and improves scanning without feeling too cramped. Line heights suitable for English are often too tight for Japanese.

In addition to line height, line length plays a crucial role in readability. Because Japanese characters carry more visual weight than Latin letters, excessively long lines can make reading feel tiring and scanning more difficult. To optimize readability:

• Keep line lengths between 40–50 characters per line for Japanese text
• Use a maximum paragraph width of 600–700px on desktop to maintain an optimal reading experience Applying both generous line height and controlled line length helps create smoother reading rhythms, clearer text blocks, and a more comfortable user experience for Japanese readers.

Left-Aligned Text

Japanese text should be left-aligned to maintain readability, natural flow, and consistent visual rhythm, while center alignment should be reserved only for titles, headings, or short taglines where balance and emphasis are needed.

Usage of List

Make sure to support and use true ordered or unordered list for bullet points (For example <ul> or <ol> in HTML). Align with the local team for correct usage and maintenance. When making localization adjustments to our components and semantics, it is important to maintain our standards of accessibility.

Truncation

It is important to remember to align your text properly within the design system components to ensure the text doesn’t truncate. Truncation reduces readability, makes the page less intuitive to use, and appears unprofessional.

Unnatural Line Breaks

Some titles and labels contains mid-word line breaks that disrupt readability and leave the UI feeling unpolished. English usually avoids this because spaces and optional hyphens tell the rendering engine where to wrap, whereas Japanese doesn’t offer such hints, so breaks can fall almost anywhere and break words or phrases.

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Date Formatting

In Japan, kanji-formatted dates are considered formal and culturally appropriate in official or polite contexts, while slash-separated dates are preferred in informal or data-heavy applications.​ To align with local conventions, use both formats as appropriate—balancing space efficiency, scannability and tone.

Kanji Format

Basic principles of Japanese date format​:

Counter	Description
年	Year
月	Month
日	Day

Slash Format

Use slash format for data tables or lists or when displaying dates related to data. Add leading zeros, especially in list views, to enhance vertical alignment and scanning.​ For slash-formatting, include the year to avoid ambiguity between date and month.

Range Indicator

Depending on the date-formatting used, use the proper dash.

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Currency Formatting

For a more formal appearance, write yen in Kanji (円) after the amount. Adjust the size and contrast of 円 to put more emphasis on the number.