Katakana

Katakana is hiragana's angular twin. Where hiragana came from writing whole cursive characters, katakana came from taking a piece of a character — a corner, a side, a few strokes — as a quick phonetic shorthand. Both syllabaries derive from kanji (Han characters), the parent script imported from China; katakana is the fragment, hiragana the flowing whole.

It was devised by Buddhist monks around the 9th century as an annotation system: small marks squeezed beside Chinese texts to note Japanese pronunciation and grammar. Its shapes are spare and sharp — ア is a fragment of 阿, カ the left side of 加, the same 加 whose cursive whole gave hiragana か. See the descent in the Han Wing.

Not the whole character, but a corner of it — a monk's shorthand in the margin.

The two syllabaries cover exactly the same set of sounds. Modern Japanese hands katakana a specific job: foreign loanwords, onomatopoeia, scientific names, and emphasis — the italic-and-capitals of Japanese. For the flowing counterpart, see its sibling hiragana; for the parent, kanji.

Each katakana sign is a fragment lifted from a kanji — a corner, a side, or a handful of strokes chosen because the whole character was read with that sound. Monks used them as glosses: quick phonetic notes wedged beside Chinese scripture to show how it should be read aloud in Japanese.