Japanese placeholder text fills CJK layouts with realistic-looking content before real copy arrives. Japanese writes without spaces, mixes three scripts, and can break lines at almost any character, so it surfaces font and wrapping problems that Latin lorem ipsum never reveals.
The three scripts of Japanese and why all three matter
Japanese uses three distinct writing systems simultaneously within the same sentence — often within the same clause. Each has different rendering characteristics:
Hiragana — the phonetic syllabary used for native Japanese words, grammatical particles, and verb endings. Every character represents a mora (syllable). Example: の、は、です.
Katakana — the phonetic syllabary used primarily for loanwords from foreign languages (especially English), scientific terms, and for emphasis. Example: コンピュータ (konpyuuta — computer), アプリ (apuri — app).
Kanji — logographic characters borrowed from Chinese, used for nouns, verb stems, and adjective roots. Each carries a meaning and multiple readings. Example: 日本 (Nihon — Japan), 時間 (jikan — time).
In natural Japanese, all three appear together in every sentence. A layout using only hiragana filler will look correct phonetically but will not surface the fixed-width geometry issues that arise when kanji and katakana (which often have tighter spacing) mix in the same text run.
Line-breaking differences from Latin text
Latin text breaks only at word boundaries (spaces). Japanese has no spaces, so the browser can break the line after almost any character. The exceptions are punctuation characters like 。 (full stop) and 、 (comma), which must not appear at the start of a new line — this is the Japanese typographic rule called kinsoku shori. A font or CSS configuration that does not implement kinsoku shori will produce orphaned punctuation at line beginnings, which is considered incorrect.
How it works
The generator draws from three pools: hiragana syllables, katakana syllables, and a set of common kanji. In mixed mode it interleaves them the way natural Japanese does, then groups the characters into sentence-like runs terminated by the full-width full stop 。 and separated by the full-width comma 、.
An optional vertical preview applies writing-mode: vertical-rl so you can see how the text reads top-to-bottom, right-to-left, as used in traditional Japanese print layouts and some website headers.
What to check in your layout
- Font completeness: Watch for characters rendered from a fallback typeface — a sure sign of incomplete CJK font coverage. The fallback glyph often has different proportions and looks visually inconsistent.
- Line breaks: Confirm that
。and、do not appear at the start of a new line. - Vertical layout: If you support vertical writing mode, check that roman numerals and numbers rotate correctly (they should be upright or rotated depending on the CSS
text-combine-uprightsetting). - Container width: Japanese fixed-width characters (full-width) are wider than typical Latin lowercase letters, so containers sized for English text often need to be wider to hold the same amount of Japanese content.
Replace placeholder filler with professionally translated copy before shipping — machine translation of Japanese is improving but still inconsistent in register and formality.