Here's a scenario:
The store has a 30% off sale today, but you bought something at full price yesterday. What do you say?
"If I'd known there'd be a sale, I would have waited."
This is a counterfactual conditional — the fact already happened (you paid full price), but you imagine an opposite condition (knowing about the sale) and state an outcome that will never come true (you would have waited).
Japanese has a fixed formula for this.
The Formula
Conditional (たら／ば) + past tense + のに
Three parts, all essential:
| Part | Function | Example |
|---|---|---|
| Conditional | Imagine a condition opposite to reality | セールになるなら |
| Past tense | State what "would have" happened | 買わずに待った |
| のに | Express regret: "but it didn't" | ……のに |
Which Conditional to Use
In counterfactuals, you can use たら, ば, or なら — but never と:
| Conditional | Usable? | Example |
|---|---|---|
| たら | Yes | もっと勉強したら、合格したのに。 |
| ば | Yes | もっと勉強すれば、合格したのに。 |
| なら | Yes | セールになるなら、買わずに待ったのに。 |
| と | No | ×もっと勉強すると、合格したのに。 |
Why not と? Because と expresses inevitable cause-and-effect (press the switch and the light turns on), which doesn't fit hypothetical scenarios.
Concrete Examples
1. Regret — If only I had known
もし早く病院に送っていたら、死なずに済んだのに。 If we had taken them to the hospital sooner, they wouldn't have died.
Fact: Taken too late; they died. Counterfactual: Imagine taking them sooner → they would have survived.
2. Blame — You should have done this
もし電話してくれたら、助けに行ったのに。 If you had called me, I would have gone to help.
Fact: You didn't call; I couldn't help. Counterfactual: Imagine you called → I would have helped.
3. Lament — It could have been prevented
お前がしっかりしていれば、あの子が事故を起こさずに済んだのに。 If you had been more responsible, that child wouldn't have had the accident.
Fact: You weren't reliable; the child had an accident. Counterfactual: Imagine you were reliable → no accident.
4. Shopping regret
セールになるなら、買わずに待ったのに。 If I'd known there would be a sale, I would have waited.
Fact: Already bought at full price. Counterfactual: Imagine knowing about the sale → would have waited.
Structural Analysis
Breaking down counterfactuals:
Fact: Didn't study much → Didn't pass
Counterfactual: もっと勉強したら → 合格したのに
Fact: Taken to hospital too late → Died
Counterfactual: 早く送っていたら → 死なずに済んだのに
Fact: You weren't reliable → Child had accident
Counterfactual: しっかりしていれば → 事故を起こさずに済んだのに
Every pair follows: Flip the fact → conditional (たら/ば) + opposite result in past tense + のに.
The Role of のに
Here のに doesn't mean "in order to" — it expresses contrastive regret — "it should have been this way, but it wasn't":
| With のに | Without のに |
|---|---|
| 合格したのに。(Would have passed, but...) | 合格した。(Passed.) |
| Carries regret | Simple statement |
のに adds a layer of "what a shame," "unfortunately," or "if only" to the sentence.
Summary
- Counterfactual = conditional (たら/ば/なら) + past tense + のに
- Cannot use と (と is for inevitable cause-and-effect, not hypotheticals)
- のに expresses regret — "it would have been this way, but it wasn't"
- The result clause must be in past tense — because you're talking about what "would have happened"
Self-Check Exercises
Q1. What is the actual fact behind 「もっと勉強したら合格したのに」?
Show Answer
The fact is: Didn't study much, so didn't pass. The speaker uses a counterfactual to express regret — "If I had studied more, I would have passed. But I didn't."
Q2. Why can't counterfactuals use と?
Show Answer
Because と expresses objective, inevitable cause-and-effect (春になると桜が咲く — when spring comes, cherry blossoms bloom). It's not suitable for expressing hypothetical situations contrary to fact. Counterfactuals need "hypothetical" conditionals, so they use たら/ば/なら.
Q3. Express this as a counterfactual: If you had come earlier, you could have seen him.
Show Answer
もっと早く来ていれば、彼に会えたのに。
Fact: You arrived late, didn't see him. Counterfactual: Imagine coming earlier → would have met him. Uses ば + past tense + のに.