Volitional Form (〜よう/〜おう): 'Let's' and 'I'll' in Plain Japanese
What it means
The volitional form expresses a will to act. With another person, it means "let's ~" — a casual invitation or suggestion. Spoken to yourself or about your own plan, it means "I'll ~" or "I think I'll ~" — a decision you've just made. It's the plain-form equivalent of the polite 〜ましょう you learned at N5, so 行こう and 行きましょう say the same thing at different politeness levels.
モチ、一緒に勉強しよう。
モチ、いっしょに べんきょう しよう。
Mochi, let's study together.
しよう = casual 'let's do.' Friendly invitation.
疲れたから、ちょっと休もう。
つかれたから、ちょっと やすもう。
I'm tired, so I'll take a little break.
A resolve said to oneself: 'I'll ~.'
ヤッタン、明日は早く起きよう。
ヤッタン、あした は はやく おきよう。
Yattan, let's get up early tomorrow.
How to form it
The volitional always ends in the o-vowel sound: る-verbs take よう, and う-verbs take 〜おう (written with the o-row kana + う).
| Verb type | Rule | Example |
|---|---|---|
| る-verb (ichidan) | drop る + よう | 食べる → 食べよう ・ 見る → 見よう |
| う-verb (godan) | final u → o + う | 行く → 行こう ・ 飲む → 飲もう ・ 話す → 話そう |
| する | irregular | する → しよう |
| 来る | irregular | 来る → 来よう（こよう） |
For う-verbs, just shift the last sound down the same column: く→こ, む→も, す→そ, う→お, ぶ→ぼ, and so on, then add う. So 買う → 買おう, 待つ → 待とう, 帰る → 帰ろう (帰る is a う-verb despite ending in る).
この映画を見よう。
この えいが を みよう。
Let's watch this movie.
先生に聞いてみよう。
せんせい に きいて みよう。
Let's try asking the teacher.
〜てみる ('try doing') in volitional → 〜てみよう.
"Let's ~" vs "I'll ~"
The same form covers both an invitation to someone else and a private decision — context tells you which. With a listener present, it pulls others in; alone, it's you talking yourself into something.
週末、海に行こう！
しゅうまつ、うみ に いこう！
Let's go to the sea this weekend!
Invitation to a friend.
よし、今日から毎日走ろう。
よし、きょう から まいにち はしろう。
All right, from today I'll run every day.
A resolution to oneself.
What it builds toward
The volitional is the base for two very common N4 patterns. You attach things directly to the volitional form:
- 〜ようと思う = "I intend / am thinking of ~." Adding と思う to the volitional turns a raw resolve into a stated plan: 日本へ行こうと思う ("I'm thinking of going to Japan"). This is closely related to 〜と思う.
- 〜ようとする = "to try / attempt to ~" (right at the moment of acting): 出かけようとした時に電話が鳴った ("the phone rang just as I was about to head out").
Both of these get their own guides in this N4 batch — for now, just notice that they start from the volitional you're learning here. They also overlap in meaning with 〜つもり, another way to talk about intentions.
Common mistakes
- Adding ます-style endings. The volitional is already plain. Say 行こう or polite 行きましょう — never mix them into 行こうます.
- Using よう on う-verbs. よう is only for る-verbs and the irregulars. う-verbs take 〜おう: 飲む → 飲もう (not 飲みよう).
- Forgetting 帰る and 入る are う-verbs. They look like る-verbs but conjugate as う-verbs: 帰ろう, 入ろう (not 帰よう).
- Treating it as a polite invitation. 行こう is casual. To a teacher, a customer, or anyone you'd use です／ます with, switch to 行きましょう.
Quick recap
- Volitional = plain "let's ~" or "I'll ~" (a personal resolve).
- る-verb: drop る + よう. う-verb: final u → o + う. する → しよう, 来る → 来よう（こよう）.
- It's the casual version of polite 〜ましょう.
- It powers 〜ようと思う ("intend to") and 〜ようとする ("try to").
Your turn
Form the volitional and choose the right 'let's / I'll' usage.
Start the 5-question drill →Take the full N4 volitional drill →
Frequently asked questions
What's the difference between 行こう and 行きましょう?
They mean the same thing — 'let's go' / 'I'll go.' 行こう is the plain (casual) volitional for friends and family; 行きましょう is the polite form for です／ます situations.
How do I make the volitional of う-verbs?
Change the final u-sound to the matching o-sound and add う: 行く → 行こう, 飲む → 飲もう, 話す → 話そう, 待つ → 待とう.
What are the irregular volitional forms?
There are two: する → しよう and 来る → 来よう (こよう). Memorize these, since they don't follow the regular rules.
Can the volitional mean a decision, not an invitation?
Yes. Said to yourself, it means 'I'll ~' as a resolve you've just made: ちょっと休もう ('I'll take a break'). Context tells you whether it's 'let's' or 'I'll'.