This is the single-shape reference for the volitional（意向形, いこうけい）— the "let's…" and "I think I'll…" form. The anchor is 書く→書こう（かこう, "let's write / I'll write"）. A 五段 verb walks its final kana to the お-row and adds う (which fuses into a long ō); a 一段 verb adds よう; する becomes しよう; 来る becomes 来よう（こよう）. The polite counterpart of the whole thing is 〜ましょう. Two ideas make this page: the plain form is where the -よう trap lives (×食べろう), and the volitional is emphatically not a future tense.
The core split: お-row+う vs +よう
A 五段 verb walks its final kana to the お-row, then adds う — and the vowel fuses into a long ō:
- 書く（ka-ku）→ 書こう（ka-ko-u → kakō）
- 話す（hana-su）→ 話そう（hanasō）
- 飲む（no-mu）→ 飲もう（nomō）
A 一段 verb adds よう to its fixed stem:
- 食べる → 食べよう（tabeyō）
- 見る → 見よう（miyō）
そろそろ帰ろうか。
sorosoro kaerō ka
Shall we head home soon?
疲れたし、今日は早く寝よう。
tsukareta shi, kyō wa hayaku neyō
I'm tired, so I'll go to bed early today.
お腹すいた。何か食べようよ。
onaka suita. nanika tabeyō yo
I'm hungry — let's grab something to eat.
The full table
| Class | Dictionary | Volitional | Reading | Rule |
|---|---|---|---|---|
| 五段 -く | 書く | 書こう | kakō | お-row + う |
| 五段 -す | 話す | 話そう | hanasō | お-row + う |
| 五段 -む | 飲む | 飲もう | nomō | お-row + う |
| 五段 -る | 取る | 取ろう | torō | お-row + う |
| 五段 -う | 買う | 買おう | kaō | お-row + う（う→お） |
| 一段 | 食べる | 食べよう | tabeyō | stem + よう |
| 一段 | 見る | 見よう | miyō | stem + よう |
| する (irregular) | する | しよう | shiyō | suppletive |
| 来る (irregular) | 来る | 来よう | koyō | こ + よう |
The -う row lands on the お-row cleanly: 買う → 買お + う = 買おう（kaō）, no わ. The volitional is one of the few forms with no irregular sound changes beyond the vowel fusion — even 行く, which breaks the te-form, is perfectly regular here: 行こう（ikō）.
The polite counterpart: 〜ましょう
Everything above is the plain volitional, for friends, family, and inner monologue. The polite equivalent is built on the ます-stem + ましょう, and it maps one-to-one:
| Plain | Polite | Reading |
|---|---|---|
| 書こう | 書きましょう | kakimashō |
| 食べよう | 食べましょう | tabemashō |
| 行こう | 行きましょう | ikimashō |
| しよう | しましょう | shimashō |
| 来よう | 来ましょう | kimashō |
では、そろそろ始めましょうか。
dewa, sorosoro hajimemashō ka
All right — shall we get started, then? (polite)
駅の改札で待ち合わせしましょう。
eki no kaisatsu de machiawase shimashō
Let's meet at the station ticket gates. (polite)
What it actually means: intention and invitation
The volitional does two jobs, both anchored in the speaker's own will:
Invitation ("let's / shall we") — often with the question particle か:
週末、天気が良かったら海でも行こうか。
shūmatsu, tenki ga yokattara umi demo ikō ka
If the weather's nice this weekend, shall we go to the beach or something?
Resolve / intention ("I'll…") — frequently with 〜(よ)うと思う (I think I'll) or 〜(よ)うとする (try to):
来年こそ、日本語を本気でやろうと思ってる。
rainen koso, nihongo o honki de yarō to omotteru
Next year for sure, I'm thinking I'll get serious about Japanese.
電車に乗ろうとしたら、目の前でドアが閉まった。
densha ni norō to shitara, me no mae de doa ga shimatta
Just as I went to board the train, the doors closed right in front of me.
The nuance difference is worth internalizing: 〜と思う is covered on volitional + と思う, and 〜とする on volitional + とする.
The insight: this is not a future tense
Here is what makes the volitional slippery for English speakers. English "will" does two unrelated jobs — neutral prediction ("it will rain tomorrow") and personal resolve ("I'll do it"). Japanese splits these. The plain non-past 書く already covers the future (明日書く = "I'll write it tomorrow"), so the volitional is reserved only for the will-and-invitation half. You can never use it for a neutral forecast: rain "will fall" is 雨が降るだろう, never ×降ろう.
明日は雨が降るだろうから、傘を持っていこう。
ashita wa ame ga furu darō kara, kasa o motte ikō
It'll probably rain tomorrow, so I'll take an umbrella.
Notice the split inside that one sentence: the prediction about rain is 降るだろう (not volitional), while the decision to take an umbrella is 持っていこう (volitional). Get this and you will stop misfiring 〜(よ)う as a general "will."
Common mistakes
❌ お腹すいた、何か食べろう。
Wrong — that ろ is the imperative ('eat!'). The 一段 volitional is よう: 食べよう. Only 五段 verbs use the お-row + う.
✅ お腹すいた、何か食べよう。
onaka suita, nanika tabeyō
I'm hungry — let's eat something.
❌ 手紙を書きよう。
Wrong base — you used the ます-stem 書き. 五段 volitional walks to the お-row: 書こう, not ×書きよう (よう belongs to 一段 verbs).
✅ 手紙を書こう。
tegami o kakō
I'll write a letter.
❌ そろそろ準備しろう。
Wrong — the volitional of する is the suppletive しよう. ×しろう mixes in the imperative ろ.
✅ そろそろ準備しよう。
sorosoro junbi shiyō
Let's start getting ready soon.
❌ また遊びに来よう。（きよう）
Right kanji, wrong reading in your head — 来よう is read こよう, never きよう. The volitional uses the こ-stem.
✅ また遊びに来よう。（こよう）
mata asobi ni koyō
Let's come hang out again.
❌ 明日は晴れよう。
Not a forecast — the volitional isn't a future/prediction 'will.' A neutral prediction uses だろう/でしょう: 明日は晴れるだろう.
✅ 明日は晴れるだろう。
ashita wa hareru darō
It'll probably be sunny tomorrow.
Key takeaways
- 書こう is the anchor. 五段 = final kana to the お-row + う (fuses to long ō); 一段 = stem + よう; する→しよう; 来る→来よう（こよう）.
- The -う row lands on the お-row (買おう), no わ; even 行く is regular (行こう).
- The polite counterpart is ます-stem + ましょう (書きましょう, しましょう).
- Uses: invitation (行こうか) and intention (やろうと思う, 乗ろうとする) — always the speaker's own will.
- It is not a future tense: plain 書く already covers the future; a prediction uses だろう/でしょう, never 〜(よ)う.
- Don't write ×食べろう or ×書きよう — the ろ is the imperative, and the ます-stem never carries よう.
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Start learning Japanese→Related Topics
- ます-Form: Conjugation TableN5 — The complete polite ます-family across every verb class — present, negative, past, past-negative, and volitional — all built on the い-row 連用形 stem.
- All Forms, All Classes: Master ChartN4 — The one-sheet everything reference — every major verb form (dictionary through causative-passive, volitional, conditional, imperative) down the side and 書く・食べる・する・来る across the top, so you can verify any form without hunting across pages.
- Imperative 命令形 & Prohibitive な: TableN3 — The blunt-command forms in one table — 五段 shift to the え-row (書け), 一段 add ろ/よ (食べろ/食べよ), する→しろ/せよ, 来る→来い, plus the prohibitive dictionary＋な (行くな) and how it differs from the softening ます-stem＋な (食べな).