Volitional Form (〜よう/〜おう): 'Let's' and 'I'll' in Plain Japanese
Building the form
The volitional always lands on 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). The form also stacks onto helper verbs like 〜てみる, which simply take their own final verb into the volitional.
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.
What it lets you say
Once you have the form, it does two jobs. 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.
The volitional is also the launchpad for two very common N4 patterns — you attach things directly to it:
- 〜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 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.
The conjugation traps
- 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.
Seeing it in context
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.
The short version
- 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").
Practice it
Form the volitional and choose the right 'let's / I'll' usage.
＿＿＿に入れるのに最もよいものを選びなさい。
Choose the grammar pattern that best completes the sentence.
ヤッタン、明日は早く＿＿＿。
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'.
Where Volitional Form fits
Don't confuse it with
- 〜でしょう / 〜だろう · N5 — でしょう means 'probably' and, with a rising tone, 'right?'. Learn how it attaches to verbs, adjectives, and nouns, its casual form だろう, and why forecasts love it.
- 〜つもり · N5 — つもり expresses a personal plan or intention: 行くつもりです ('I plan to go'). Learn the dictionary-form pattern, negatives, つもりだった, and how it differs from よてい and 〜よう.
Once this clicks, go on to
- 〜と思う · N5 — 〜と思う lets you say what you think: [plain form] + と思う. Learn the quotative と, why the clause stays plain, the 〜ようと思う 'I'm thinking of doing' use, and 〜と思っている.
More N4 grammar to explore
Keep going with related patterns at the same level:
- 〜ようと思う — 〜ようと思う uses the volitional form + と思う to say you've decided to do something: 勉強しようと思う. Learn the formation, the 〜ようと思っている variant, and how it differs from つもり and 予定.
- 謙譲語 — 謙譲語 (kenjougo) is humble Japanese: you lower yourself and your group to honor others. Learn the お〜する pattern and special humble verbs like 参る, いたす, 申す, and 伺う.
- 〜のに — This 〜のに attaches to a dictionary-form verb to mean 'for doing X' or 'in order to X', setting up a comment about time, cost, or usefulness — 行くのに1週間かかった (it took a week to go). Not the same のに as 'even though'.
- 尊敬語 — Sonkeigo (尊敬語) raises the person you're talking about — the listener or a third party — never yourself. Learn お〜になる, お〜ください, the passive honorific, and the special verbs.
- 〜そうに/そうな — 〜そうに (adverbial) and 〜そうな (adnominal) attach to an adjective or verb stem to mean 'looking like/seeming to' — 楽しそうに話す ('talk looking happy'), 美味しそうな料理 ('food that looks delicious'). They describe an appearance judged from what's visible.
- 〜たがる — 〜たがる expresses a third person's desire ('he wants to…'). Learn why Japanese switches from たい to たがる, how to form it, the particle change, and see clear examples.