change-of-state verb

Verbs that describe entering a new state, intransitively, without an external agent — 疲れる ('get tired'), 開く ('open'), 壊れる ('break'), 生まれる ('be born'), 死ぬ ('die'), 落ちる ('fall'), 治る ('recover'). Their past tense typically marks the moment of transition; their ~ている form expresses the resulting ongoing state. English often handles these with passives ('be born,' 'be cured'), but Japanese marks them as plain intransitive events.