Look at these three sentences:
A. ラーメンを食べよう。 B. 午後から雨が降るでしょう。 C. この映画を見ようか。
All three involve the volitional form, but mean completely different things:
- A = I'm going to eat ramen! (Volition)
- B = It'll probably rain this afternoon. (Conjecture)
- C = Shall we watch this movie? (Invitation)
How to Conjugate
| Verb type | Dictionary | Volitional |
|---|---|---|
| Godan | 書く | 書こう |
| Godan | 飲む | 飲もう |
| Ichidan | 食べる | 食べよう |
| カ変 | 来る | 来よう (こよう) |
| サ変 | する | しよう |
Godan: change the う-row to お-row + う. Ichidan: drop る + よう.
Use 1: Volition — "I Will!"
Expresses the speaker's determination or intention. The subject is always first person.
-
明日から毎日運動しよう。 → I'm going to exercise every day starting tomorrow! (Personal resolve)
-
今年こそ日本語の試験に合格しよう。 → This year I will pass the Japanese exam! (Strong determination)
Note: The volition use can only have "I" as the subject. You can't use the volitional form to express someone else's intention — you don't know what others are thinking.
Common Patterns with Volition
| Pattern | Meaning | Example |
|---|---|---|
| 〜ようと思う | I'm planning to... | 来月引っ越そうと思っている。 → I'm planning to move next month. |
| 〜ようとする | To try to... / About to... | 出かけようとした時、電話が鳴った。 → Just as I was about to leave, the phone rang. |
Use 2: Conjecture — "Probably..."
Making a guess or prediction about something. Often paired with「でしょう」or「だろう」.
-
午後から雨が降るでしょう。 → It will probably rain this afternoon.
-
彼はもう帰っただろう。 → He's probably already gone home.
-
この問題は難しいでしょう。 → This problem is probably quite difficult.
Telling volition and conjecture apart is simple: "I" + action = volition. Other person/thing as subject = conjecture.
Use 3: Invitation — "Shall We?"
Used to invite someone or suggest doing something together. Usually ends with「か」.
-
一緒にご飯を食べようか。 → Shall we eat together?
-
この映画を見ようか。 → Shall we watch this movie?
-
そろそろ帰ろうか。 → Shall we head back soon?
Without「か」→ leans toward personal volition. With「か」→ becomes an invitation or suggestion to the listener.
Quick Reference Table
| Use | Subject | Nuance | Example |
|---|---|---|---|
| Volition | I | I'm determined to do this | 頑張ろう！ |
| Conjecture | Others / things | Probably... | 明日は晴れるだろう。 |
| Invitation | We | Shall we? | 行こうか。 |
Self-Test
Q1. 「明日は寒くなるだろう。」— which use is this?
Show answer
Conjecture. The subject is the weather (a thing), making a prediction that tomorrow will be cold.
Q2. 「今日は早く寝よう。」— volition or invitation?
Show answer
Volition. There's no「か」— it's a personal decision to sleep early tonight. Adding「か」to make「早く寝ようか」would turn it into an invitation/suggestion ("shall we go to sleep early?").
Q3. Rewrite using the volitional form: 「来月日本に行くつもりだ。」→ ＿＿と思っている。
Show answer
来月日本に行こうと思っている。 「〜ようと思っている」expresses an ongoing intention, similar in meaning to「つもりだ」.
Summary
- The volitional form has three uses: volition (I will!), conjecture (probably), and invitation (shall we?)
- The key to telling them apart is the subject: I = volition, others/things = conjecture, we = invitation
- Adding「か」at the end turns volition into invitation
- Common patterns: 〜ようと思う (planning to), 〜ようとする (trying to / about to)