～かろう

• Reading: かろう
• Romaji: karou
• Formation: Adj-い stem + かろう (高い → 高かろう) / Verb-ない stem + かろう (ない → なかろう)

Meaning

A literary auxiliary indicating the writer's conjecture or supposition, not based on any particular evidence. It is the written equivalent of だろう for adjectives.

かろう is a formal, literary form used primarily in written Japanese to express conjecture. It attaches to the stem of い-adjectives (replacing the final い) and to certain negative forms. For example, 高い becomes 高かろう and ない becomes なかろう. This form is rarely used in everyday conversation and is largely confined to essays, literary works, newspaper editorials, and formal speeches. It carries an older, more dignified tone compared to だろう. Learners should recognize this form in reading but use だろう or でしょう in most practical situations.

Examples

1. この計画の実現は難しかろう。 Realizing this plan will likely be difficult.
2. 彼の苦労は並大抵ではなかろう。 His hardships are presumably no ordinary matter.
3. 結果がどうであれ後悔はなかろう。 Whatever the result, there will likely be no regrets.

Usage Guide

Context: written, literary, formal speech

Tone: contemplative

Do Say

• いくら説明しても理解しがたかろう。
• この改革には反対も多かろう。
• 事情は複雑であり、簡単には解決できなかろう。

Don't Say

• 明日は寒いかろう。(Using かろう in casual conversation — it sounds overly literary and unnatural in speech) → 明日は寒いだろう。
• この映画は面白いかろう。(Attaching かろう to the full adjective instead of the stem — must drop い first) → この映画は面白かろう。

Origin & History

Derived from the classical Japanese conjectural ending かろう, which was the volitional form of the adjective auxiliary かり. It persists in modern formal writing as an archaic conjecture marker.

Cultural Context

Generation: All ages

Social background: Universal