Japanese has four main conditional forms, and they are not interchangeable. English collapses them all into "if" (and sometimes "when"), which is exactly why learners stall here. The good news: each has a clear core meaning, and one of them (たら) is a safe default when you're unsure.
と — automatic consequence
と says: whenever A, B inevitably follows. General truths, natural results, machine behavior, directions. The main clause cannot be a command, request, or statement of intention — if you want those, you need a different form.
| Japanese | Reading | Meaning |
|---|---|---|
| 春になると暖かくなる | haru ni naru to atatakaku naru | when spring comes, it gets warm |
| ボタンを押すとドアが開く | botan o osu to doa ga aku | press the button and the door opens |
ば — provisional / general condition
ば states a hypothetical condition with the focus on the condition itself: "if A (holds), then B." It's the form of proverbs and general "if it were so" statements. (The Verb Conjugation guide covers how to build the ば-form.) When the two clauses have different subjects and the main clause is volitional, ば gets awkward — reach for たら or なら instead.
| Japanese | Reading | Meaning |
|---|---|---|
| 安ければ買う | yasukereba kau | if it's cheap, I'll buy it |
| 練習すれば上手になる | renshū sureba jōzu ni naru | if you practice, you get good |
たら — the versatile one
たら is the workhorse: "if/when A is done, then B." It handles one-off future situations, and uniquely it covers past discovery — "when A happened, B turned out to be the case." It's the most spoken-language-friendly of the four and the one to default to when the others feel uncertain.
| Japanese | Reading | Meaning |
|---|---|---|
| 雨が降ったら行かない | ame ga futtara ikanai | if it rains, I won't go |
| 家に帰ったら誰もいなかった | ie ni kaettara dare mo inakatta | when I got home, nobody was there |
なら — given that / speaking of
なら picks up a premise — often something just said or a topic — and responds to it: "if that's the case / if we're talking about A, then B." Unlike たら, the なら-clause doesn't have to happen first; it can even precede A in time. It's how you give advice keyed to what someone just told you.
| Japanese | Reading | Meaning |
|---|---|---|
| 日本に行くなら京都がいい | nihon ni iku nara kyōto ga ii | if you're going to Japan, Kyoto is good |
| 寿司なら、あの店だ | sushi nara, ano mise da | when it comes to sushi, [it's] that shop |
Quick comparison
| Form | Core sense | Reach for it when |
|---|---|---|
| と | inevitable result | general truths, instructions, machine behavior |
| ば | hypothetical condition | proverbs, "if it were so", focus on the condition |
| たら | if / when, then | one-off situations, past discovery, unsure — default |
| なら | given that premise | responding to what was said, advice, topics |
Counterfactual regret
Pair ば or たら with a clause ending in のに to express "if only…": a wish or regret about something that didn't happen. もっと早く言ってくれたら、 よかったのに — "if you'd told me sooner, it would've been good (but you didn't)."