意向形【いこうけい】

The 意向形 (volitional form) is used to express a speaker's will or intention to do something, or to suggest or invite someone to do something together. It is equivalent to "let's ~" or "I'll ~" / "shall we ~" in English.

Formation

Godan (V5) verbs: Change the final う-column kana to the corresponding お-column kana and add う.

• かう買う → 買おう - まつ待つ → 待とう - のむ飲む → 飲もう - かく書く → 書こう - はなす話す → 話そう - およぐ泳ぐ → 泳ごう - あそぶ遊ぶ → 遊ぼう - とる取る → 取ろう Ichidan (V1) verbs: Remove る and add よう.
• たべる食べる → 食べよう - みる見る → 見よう Irregular verbs:
• する → しよう - くる来る → 来よう（こよう）

The polite equivalent is 〜～ましょう (V[stem] + ましょう).

Suggesting or inviting – "Let's ~"

The most common use of the volitional form is to propose doing something together with the listener.

Adding か to the polite volitional makes a polite invitation or suggestion ("shall we ~?"):

Expressing personal intention – "I'll ~"

When used by itself (often as an inner thought or casual statement), it expresses the speaker's intention or decision.

Common related patterns

～ようと思う – "I think I'll ~" / "I'm planning to ~". Used to express a softer or more considered intention.

～ようとする – "to try to ~" / "to be about to ~". Describes an attempt or the moment just before an action.

Casual vs. polite

The plain volitional (e.g. いこう行こう) is casual and used with friends or family. The polite form 〜～ましょう (e.g. いきましょう行きましょう) is appropriate in formal situations or with people you are not close to.