已い然ぜん形けい

noun

realis form; perfective form

In classical Japanese grammar, the 已然形 is a verb/adjective form used to express realis (already realized) conditions, often followed by ば to mean 'since' or 'because'. In modern Japanese, it corresponds to the 仮定形 (hypothetical form) when followed by ば, but the classical 已然形＋ば indicates a reason, not a hypothesis.

See also: 仮定形 (かていけい)

• 古こ典てん文ぶん法ぽうでは、「已い然ぜん形けい＋ば」は原げん因いん・理り由ゆうを表あらわす。

  In classical grammar, 'realis form + ば' expresses a cause or reason.

• 「書かけば」の「書かけ」は、現げん代だい語ごでは仮か定てい形けいだが、古こ典てんでは已い然ぜん形けいとされる。

  The '書け' in '書けば' is the hypothetical form in modern Japanese, but it is considered the realis form in classical Japanese.