English has one conditional word, if, and it does everything: "if you push it," "if it's cheap," "if you're going to Japan," "if I have time." Japanese fans that single word out into four — と, ば, たら, and なら — and the whole difficulty of Japanese conditionals is learning to choose among them. This is the page that teaches the choice.
The good news: you do not pick by tossing a coin. You pick by asking two questions — what is in the main clause? and where does the condition come from? Once you have those two reflexes, the four forms sort themselves out.
The one-glance table
| Form | Attaches to | Core meaning | Main clause can be a command/request/plan? | Gloss |
|---|---|---|---|---|
| と | plain non-past (押す, ない) | automatic, inevitable result | No | whenever X, (always) Y |
| ば | provisional (押せば, なければ) | general / hypothetical condition | Awkward if same subject | if X (were to) |
| たら | plain past + ら (押したら) | specific one-time if / when | Yes — freely | if / once / when X |
| なら | plain form (行くなら) / noun (日本なら) | given the topic/premise just raised | Yes | if it's the case that X |
Keep that fourth column in view — the main clause is your fastest filter. If what follows "if" is an order, a request, or a plan, と is out immediately, and usually ば is too. That alone narrows most sentences to たら or なら.
The same idea in all four forms
Nothing teaches the difference like running one condition — 時間がある ("there is time") — through every form. Watch the meaning shift.
時間があると、つい本を読んでしまう。
jikan ga aru to, tsui hon o yonde shimau
Whenever I have time, I (always) end up reading. — と: an automatic, habitual result.
時間があれば、参加します。
jikan ga areba, sanka shimasu
If I have time, I'll take part. — ば: a plain, general hypothetical condition.
時間があったら、映画でも見に行こう。
jikan ga attara, eiga demo mi ni ikō
If/when I have time, let's go see a movie or something. — たら: a specific occasion, and the main clause is an invitation.
時間があるなら、これも手伝ってくれない？
jikan ga aru nara, kore mo tetsudatte kurenai?
If you (say you) have time, could you help with this too? — なら: reacting to what the other person just implied.
Read those four out loud. と reports a reliable tendency about yourself. ば sets up a neutral condition for a plain result. たら pins it to one occasion and lets you invite. なら picks up on the listener's situation and responds to it. Same three words — 時間がある — four genuinely different sentences.
と: the automatic switch
Use と when X reliably, mechanically produces Y — natural laws, machines, directions, math, and habits. There is a sense of "every single time." Crucially, と cannot be followed by a command, request, invitation, or statement of your own will, because you do not order an inevitable result to happen.
このボタンを押すと、ドアが開きます。
kono botan o osu to, doa ga akimasu
If you push this button, the door opens.
まっすぐ行くと、右に駅があります。
massugu iku to, migi ni eki ga arimasu
If you go straight, there's a station on the right.
Directions work with と precisely because "the station appears" is not something you control — it is just what is there. The full behavior of と, including its own discovery use in storytelling, is on the と conditional page.
ば: the general hypothetical
ば is the abstract, "in principle" conditional. It leans toward stative or evaluative results — prices, feelings, judgments, "it would be good if" — and toward proverbs and general truths. Its restriction is subtler than と's: ば dislikes a same-subject volitional or command main clause. 東京に行けば、寿司を食べてください sounds off, because both clauses are about the listener's controlled action.
安ければ買うけど、高ければやめる。
yasukereba kau kedo, takakereba yameru
If it's cheap I'll buy it, but if it's expensive I'll pass.
練習すれば、きっと上手になりますよ。
renshū sureba, kitto jōzu ni narimasu yo
If you practice, you'll surely get good at it.
ば also builds two hugely common idioms — regret (〜ばよかった) and advice (〜ばいい) — covered on 〜ばよかった & 〜たらどう: regret and advice. Full formation is on the ば conditional page.
たら: the flexible one-time if/when
たら is the specific, one-occasion conditional, and — as covered in depth on its own page — it is the only one that lets the main clause be anything: a command, a request, an invitation, or a plan. That freedom is why たら is the safe default when you are unsure.
駅に着いたら、電話してください。
eki ni tsuitara, denwa shite kudasai
When you get to the station, please call me.
仕事が終わったら、飲みに行きませんか。
shigoto ga owattara, nomi ni ikimasen ka
Once work is done, shall we go for a drink?
なら: reacting to what was just raised
なら is the odd one out, and the one English speakers most often miss, because it is not really about time or inevitability — it is about taking up a topic or premise that is already on the table, often something the other person just said, and responding to it. "If that's the situation, then here's my suggestion." Its full treatment is on the なら conditional page; here is the essential feel:
日本に行くなら、京都がいいよ。
Nihon ni iku nara, Kyōto ga ii yo
If you're going to Japan, Kyoto's a good choice.
そんなに疲れているなら、今日は休んだら？
sonna ni tsukarete iru nara, kyō wa yasundara?
If you're that tired, why not take today off?
なら has a signature trick the other three cannot do: its main clause can happen before the condition in time. In 日本に行くなら、ガイドブックを買っておいたほうがいい ("if you're going to Japan, you should buy a guidebook first"), you buy the guidebook before going. With たら/と/ば, the main clause always follows the condition. That reversal is a dead giveaway that なら is the right form.
The two-question decision procedure
Do not memorize a rule per verb — run this on any sentence:
Question 1 — What is in the main clause?
- A command, request, invitation, or plan? → と is out. ば is probably out too if the subject is the same. You want たら (or なら).
- An automatic, uncontrollable result ("it opens," "you'll see the station")? → と is the crispest.
- An evaluation or "it would be good" ("you'd get better," "it'd be cheaper")? → ば fits well.
Question 2 — Where does the condition come from?
- Are you picking up something the other person just said or a premise already established, and reacting to it? → なら.
- Is it a fresh, one-time event on a specific occasion? → たら.
- Is it a general law or repeated tendency? → と (inevitable) or ば (hypothetical).
Run the earlier station example through it: the main clause is 電話してください, a request → と is out → it is a fresh one-time event → たら. 駅に着いたら電話してください. The procedure delivers the right form without you having to feel your way there.
Common mistakes
❌ 京都に行くと、お土産を買ってきて。
Kyōto ni iku to, omiyage o katte kite
Incorrect — と can't be followed by a request.
✅ 京都に行ったら、お土産を買ってきて。
Kyōto ni ittara, omiyage o katte kite
When you go to Kyoto, buy me a souvenir. (たら allows the request.)
❌ 家に帰るなら、手を洗う。
ie ni kaeru nara, te o arau
Incorrect for 'when I get home I wash my hands' — なら doesn't mark a time sequence.
✅ 家に帰ったら、手を洗う。
ie ni kaettara, te o arau
When I get home, I wash my hands. (A one-time sequence → たら.)
❌ 日本に行けば、京都に行ってください。
Nihon ni ikeba, Kyōto ni itte kudasai
Incorrect — ば resists a same-subject command in the main clause.
✅ 日本に行くなら、京都に行ってください。
Nihon ni iku nara, Kyōto ni itte kudasai
If you're going to Japan, please visit Kyoto. (Reacting to their plan → なら.)
❌ このボタンを押したら、必ず電気がつきます。
kono botan o oshitara, kanarazu denki ga tsukimasu
Understandable but weak — a fixed mechanical law is better with と.
✅ このボタンを押すと、電気がつきます。
kono botan o osu to, denki ga tsukimasu
If you push this button, the light comes on. (Automatic result → と.)
Key takeaways
- Four conditionals, two questions. Choose by the main clause first, then by the source of the condition.
- と = automatic/inevitable, no command in the main clause.
- ば = general hypothetical, prefers stative/evaluative results, dislikes same-subject commands.
- たら = specific one-time if/when, the flexible default that accepts any main clause.
- なら = reacting to a just-raised topic; the only one whose main clause can precede the condition in time.
- When the two questions don't point cleanly anywhere, たら is the safe default and ば the plain hypothetical.
Now practice Japanese
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Start learning Japanese→Related Topics
- と: Natural ConsequenceN4 — The conditional と for automatic, inevitable, and habitual results — directions, machines, and nature — and its signature ban on commands, requests, and intentions in the main clause.
- ば: Provisional ConditionN4 — The provisional conditional ば — how to form it across all verb and adjective classes, why it favors general truths and stative results, the ば〜ほど pattern, and its restriction on same-subject commands.
- たら: The Versatile If/WhenN4 — How to form and use 〜たら, the most flexible Japanese conditional, which covers both 'if' and 'when' and freely allows requests, commands, and invitations in the main clause.
- たら for Discovery & Unexpected ResultsN3 — How 〜たら with a past-tense main clause stops being a condition and becomes 'when I…, I found that…' — the discovery reading that reports something unexpected.
- なら: The Copula ConditionalN4 — The conditional derived from the copula — なら sets up a contextual 'if it's the case that / as for' frame, typically responding to a topic the conversation just raised.
- と・ば・たら・なら: Choosing a ConditionalN3 — A decision procedure for Japanese's four conditionals — two quick diagnostic tests on the main clause settle most sentences before you even weigh 'meaning'.