“〜tara”: Post-Completion Condition / Established Fact / Discovery [JLPT N4]
Content by NTJ Kuma · Nihongo to Japan editorial team · Updated July 27, 2026
「宿題をやったら遊んでいい」「窓を開けたら雪が降っていた」 — the all-purpose “if / once,” plus discovery.
「宿題やったら遊ぶ」 — the most versatile conditional 「〜たら」
「宿題をやったら、遊んでもいい」 (once you finish homework, you may play), 「家に帰ったら、雨だった」 (when I got home, (I found) it was raining) — 「(verb た-form) ＋ ら」 is Japanese's most versatile conditional, covering three uses: ① after completion (once… then); ② hypothesis (if…); ③ discovery (did… and found). This guide covers 「たら」's attachment and three uses, and separates it from the conditionals 「ば／と」 (detailed comparison in the 〈たら vs と〉 guide).
Core: with the former done／true as a premise, the latter happens
「〜たら」 = “if ~, after ~,” premised on the former being done／true:
- ① After completion (once… then): 宿題をやったら、遊ぶ (once homework's done, play).
- ② Hypothesis (if…): 雨が降ったら、中止 (if it rains, cancel).
- ③ Discovery (did… and found): 窓を開けたら、雪だった (opened the window and (found) it snowing).
Attachment: verb た-form ＋ ら (帰る→帰った→帰ったら), i-adj／noun／na-adj ＋ だったら.
How to Connect
| Form | Use | Example |
|---|---|---|
| verb た-form ＋ ら | after completion／hypothesis | 帰ったら |
| i-adjective: 〜かったら | hypothesis | 高かったら |
| noun／na-adj: 〜だったら | hypothesis | 雨だったら |
| past (〜たら、〜た) | discovery | 開けたら、〜だった （when I opened it, it turned out to be …） |
例句（看情境）
- 宿題をやったら、遊んでもいいよ。(Once your homework's done, you may play.) — after completion
- 雨が降ったら、試合は中止です。(If it rains, the match is off.) — hypothesis
- 家に帰ったら、誰もいなかった。(When I got home, (I found) no one there.) — discovery
- お金があったら、旅行したい。(If I had money, I'd want to travel.) — hypothesis
- 窓を開けたら、富士山が見えた。(I opened the window and (there) saw Mt. Fuji.) — discovery
⚠️ Easy traps to avoid
① Attaches to the “た-form,” not the dictionary form. 帰ったら (✗ 帰るたら), 食べたら (✗ 食べるたら). 「たら」 always takes the past た-form (make the た-form, then add ら).
② 「たら」 can be followed by volition, commands, requests. This is たら's most versatile point — 家に帰ったら、電話して (call me once you get home, a request follows). 「と」 can't do this (と can't be followed by commands or requests).
③ The “discovery” use is in the past. You did something and unexpectedly found a situation — both clauses past: 開けたら、雪だった (opened (the window) and (found) it snowing). This 「〜たら、〜た」 discovery use is very everyday.
🔄 Compare: たら／ば／と
| Form | Nuance | Example |
|---|---|---|
| 〜たら | most versatile (completion/hypothesis/discovery) | 帰ったら電話して |
| 〜ば | hypothetical condition (general, proverbs) | 安ければ買う |
| 〜と | inevitable, natural result | 春になると咲く |
💡 Learning tip
「たら」 is Japanese's most versatile conditional — when unsure which conditional to use, たら is almost always right. Three uses: ① after completion (宿題やったら遊ぶ = play once done); ② hypothesis (雨が降ったら中止 = if it rains, cancel); ③ discovery (帰ったら誰もいなかった = got home and found no one). Its greatest strength is that volition, commands, and requests can follow (家に帰ったら電話して = call me once home) — something 「と」 can't do. The attachment is simply verb た-form ＋ ら. For the fine difference between たら and と, see the 〈たら vs と〉 guide; for the full comparison of たら/ば/と, see the 〈conditionals overview〉.
❓ FAQ
Q: Which is most useful — 「たら」, 「ば」, 「と」?
「たら」 is the most versatile and safest — when unsure which conditional, たら is almost always natural. It covers “after completion (once… then), hypothesis (if…), discovery (did and found),” and volition, commands, requests, and invitations can follow (帰ったら電話して = call me once home). 「ば」 leans “general hypothesis” (proverbs, rules: 安ければ買う); 「と」 leans “inevitable, natural result” (春になると咲く, no commands after). Beginners: master 「たら」 first — most practical.
Q: How does 「たら」 attach, and how do I tell its three uses apart?
Attachment: verb た-form ＋ ら (帰る→帰った→帰ったら), i-adjective 〜かったら, noun／na-adj 〜だったら. Tell the three uses by context: ① after completion = the former is done, then the latter (宿題をやったら遊ぶ); ② hypothesis = the former hasn't happened, assume it does (雨が降ったら中止); ③ discovery = both past, you did something and unexpectedly found (開けたら雪だった = opened the window and found it snowing). The same 「たら」, told by context.
🖊️ Practice Quiz
Q1. 雨が降ったら、試合は_____。
(A) 開始 (B) 中止 (C) 延期 (D) 早く
Q2. 宿題を_____、遊んでもいいです。
(A) やる (B) やったら (C) やった (D) やりません
Q3. この映画を_____、きっと感動する。
(A) 見たら (B) 見る (C) 見れば (D) 見て
Q4. 家に_____、すぐにシャワーを浴びます。
(A) 帰る (B) 帰ったら (C) 帰れば (D) 帰って
Q5. お金が_____、新しい車を買いたい。
(A) あれば (B) ある (C) あったら (D) ない
Answer Key
1. (B) 中止 ── 〜たら expresses a condition: if it rains, the match is cancelled.
2. (B) やったら ── needs the たら conditional: 宿題をやったら、遊んでもいい.
3. (A) 見たら ── 〜たら as a completed-then condition: 見たら、感動する.
4. (B) 帰ったら ── 帰ったら、シャワーを浴びる (after getting home).
5. (C) あったら ── お金があったら、車を買いたい (if I had money).