開く
あく
hepburn aku
to open (intransitive)
Part of speech · godan-verb
Pattern visualization
Examples
- 自動でドアが開きました。The door opened automatically.
- 店は何時に開きますか。What time does the shop open?
Collocations
開く (aku, to open, intransitive)開ける (akeru, to open, transitive)閉まる (shimaru, to close, intransitive)営業 (eigyou, business hours)オープン (oopun, opening of shop)
Mnemonic
Aku (開く) is a godan intransitive — "to open (by itself)." Transitive partner akeru (開ける, ichidan). The same kanji 開く reads as aku (intransitive everyday) or hiraku (intransitive / transitive, more formal / abstract). Me wo akeru (open one's eyes, transitive akeru), doa ga aku (door opens, intransitive aku), kaigi wo hiraku (hold a meeting, transitive hiraku, formal). Shop terminology: kaiten (opening of a shop), oopun (loanword "open"). The intransitive / transitive family ~ku / ~keru parallels ~aru / ~eru (tomaru / tomeru, shimaru / shimeru) — chart them together. Korean "yeolida / yeolda" maps onto Japanese plus the aku / hiraku polyphonic layer.
Quick check
Two readings of 開く and their axes?