What is haiku?
俳句 (haiku) is a form of Japanese poetry consisting of three lines with a 5-7-5 mora (sound unit) structure. A mora in Japanese is roughly equivalent to one syllable — each hiragana character represents one mora. The form was developed and codified by the poet Matsuo Bashō (松尾芭蕉, 1644–1694), whose travel journals and poems remain among the most studied texts in Japanese literature.
What makes haiku distinctive is not just its brevity but its requirements: a 季語 (kigo — season word) that grounds the poem in a specific time of year, and a 切れ字 (kireji — cutting word) that creates a juxtaposition or pause between two images.
Bashō's most famous haiku
古池や 蛙飛び込む 水の音 (Furu ike ya / kawazu tobikomu / mizu no oto — The old pond — a frog jumps in — sound of water). This seventeen-mora poem is arguably the most famous haiku ever written. Its season word is 蛙 (frog — a spring kigo). The cutting word は (ya) separates "old pond" from the action that follows. In seventeen sound units, Bashō captures stillness, action, and the sudden awareness of a moment.
The season word (季語, kigo) requirement means that haiku is inseparable from Japanese seasonal culture. Books called 歳時記 (saijiki) — seasonal almanacs — catalogue thousands of approved kigo for use in haiku. A haiku without a season word is technically a 川柳 (senryū), a related but distinct form focused on human observation rather than nature.
Key haiku vocabulary and kanji
Understanding haiku requires seasonal vocabulary: 桜 (cherry blossom — spring), 蝉 (cicada — summer), 紅葉 (autumn leaves — autumn), 雪 (snow — winter). The emotional tone vocabulary: 寂しさ (sabishisa — loneliness), 静けさ (shizukesa — stillness), 清々しい (sugasugashii — fresh and clear). The observation vocabulary: 光 (light), 影 (shadow), 音 (sound), 香り (fragrance).
Explore seasonal kanji
See the dedicated kanji pages for each season and nature symbol.