LESSON NOTES · レッスンノート

N4Grammar, one piece at a time · Sep 13, 2026

Japanese conditionals: と, ば, たら and なら, and how to stop guessing

Japanese has four conditionals because they are not four ways to say the same thing: と says a result is automatic, ば says it is hypothetical, たら says it is a specific event, and なら responds to something already on the table.

Nearly every learner hits a wall here, and the wall is always the same shape: a textbook gives all four with the translation "if," so any of them looks usable, and then a teacher marks one wrong without being able to explain why in one sentence. The fastest way out is to stop asking "which one means if" and start asking "what kind of connection am I claiming?"

The basics

と — when the result is automatic

と says: whenever A happens, B follows. Laws of nature, machines, directions, habits. No opinion, no choice, no surprise.

はるになると、さくらきます。 — When spring comes, the cherry blossoms bloom. このボタンをすと、みずます。 — If you press this button, water comes out. みぎがると、えきがあります。 — If you turn right, there's the station.

Formation is the easiest of the four: plain non-past verb + と. くと, べると, たかいと, しずかだと, 学生がくせいだと.

The rule that matters is what you are not allowed to put after it. Because と claims the result is automatic, the second half cannot be something a person chooses: no commands, no requests, no invitations, no "let's," no "I will."

時間じかんがあると、てください。 。○ 時間じかんがあったら、てください。 — If you have time, please come.

If your sentence ends in ください, ましょう, つもり, or a command, と is already wrong before you finish writing it.

ば — when it is hypothetical

ば is the abstract, textbook "if A, then B." It is the conditional of general truths, advice, and things that have not happened.

Formation: change the final -u of the plain form to -eba.

Type Plain ば form
Group 1 verb けば
Group 2 verb べる べれば
する する すれば
れば
い-adjective たか たかければ
Negative verb かない かなければ
な-adj / noun しずかだ / 学生がくせい しずかなら(ば) / 学生がくせいなら(ば)

That negative row should look familiar — it is the same 〜なければ that builds 〜なければならない, "must". The "must" grammar is literally "if you don't, it won't do."

やすければいます。 — If it's cheap, I'll buy it. 練習れんしゅうすれば上手じょうずになります。 — If you practise, you'll get better.

ば has its own restriction, and it is subtler than と's: when the second half is a request or a command, the first half normally has to be a state — an adjective, a potential, an existence — not a plain action.

やすければってください。 — If it's cheap, please buy it. (state: cheap)東京とうきょうけば、連絡れんらくしてください。 (action: going — sounds off)東京とうきょうったら、連絡れんらくしてください。 — When you get to Tokyo, please contact me.

たら — the one that always works

たら is the specific, one-time conditional, and it is the most forgiving of the four. Take the plain past form and add ら. That is the entire rule, and it has no exceptions — if you can make the past tense, you can make たら.

Plain past たら form
った ったら
べた べたら
した したら
たら
たかかった たかかったら
学生がくせいだった 学生がくせいだったら

あめったら、きません。 — If it rains, I won't go. いえかえったら、電話でんわします。 — When I get home, I'll call. 日本にほんったら、カメラをいます。 — When I go to Japan, I'll buy a camera. (buying it there)

Notice the second and third examples translate as "when," not "if." たら covers both, because it is about a specific event on a timeline: once A happens, B. That timeline logic is why it accepts requests, commands, and plans where と and ば refuse.

If you are unsure which conditional to use, use たら. It is the least likely to be flatly wrong, and it is what native speakers reach for most in everyday conversation.

なら — when you are responding to something

なら does something the other three cannot: it picks up information that is already in the room and builds on it.

A: 京都きょうときたいんですが。 — I'd like to go to Kyoto. B: 京都きょうとなら、あきがいいですよ。 — If it's Kyoto (you're talking about), autumn is good.

Attach なら straight to a noun, or to the plain form of a verb or adjective. No conjugation, no だ.

コーヒーなら、あのみせがおいしいです。 — If it's coffee you want, that shop is good. つかれているなら、やすんだほうがいいですよ。 — If you're tired, you should rest.

That last one pairs naturally with ほうがいい for giving advice — なら sets up the other person's situation, ほうがいい delivers the suggestion.

Beyond the basics

The one contrast that decides たら vs なら

This pair is the sharpest test in the whole grammar point, because only the conditional changes and the meaning flips:

日本にほんったら、カメラをいます。 — When I go to Japan, I'll buy a camera. (I buy it in Japan) 日本にほんくなら、カメラをいます。 — If I'm going to Japan, I'll buy a camera. (I buy it before I leave)

たら puts B after A on the timeline. なら does not — it just takes A as a given premise, and B can happen before, during, or after. This is why なら is the conditional for preparations, advice and reactions, and why it is the only one that can put the main clause earlier in time.

Why does 〜と keep showing up in narration?

Because と has a second job that has nothing to do with "if": with a past-tense main clause, it marks discovery — you did something, and something unexpected turned out to be the case.

まどひらけると、ゆきっていました。 — When I opened the window, it was snowing. ふとがつくと、もうあさだった。 — Before I knew it, it was already morning.

You will see this constantly in novels and hear it in anime narration. It is not a conditional at all here — it is a camera move.

たら does this too, with a slightly more surprised feel: まどひらけたら、ゆきっていた lands closer to "I opened the window and — snow."

What is 〜ばよかった?

The ば form plus よかった is how Japanese expresses regret about something you didn't do:

もっと勉強べんきょうすればよかった。 — I should have studied more. (and I didn't) かなければよかった。 — I shouldn't have gone.

It is one of the highest-value phrases in the language for actual conversation, and it is the main reason to learn the ば conjugation even though たら is more flexible.

What does もし actually do — and what about もしも and もしかして?

もし is not a conditional. It is a flag you put at the front of the sentence to announce in advance that a condition is coming, and the sentence works identically without it. It pairs with all four forms — もし〜たら, もし〜なら, もし〜ば — and adds no grammar of its own.

もしあめったら、中止ちゅうしします。 — If it rains, we'll cancel. (polite) あめったら、中止ちゅうしします。 — If it rains, we'll cancel. (polite — identical meaning, and more common)

Three relatives worth separating, because they look alike and do different jobs:

Word What it does Example
もし Flags a hypothetical もし時間じかんがあったら
もしも The heavier, more remote version もしもぼくとりだったら
もしかして "Could it be that…?" — a guess about the present もしかして、日本人にほんじんですか
もしかしたら "Possibly" — pairs with かもしれない もしかしたらおくれるかもしれません

もしかして and もしかしたら are not conditionals at all despite the shape. They express a suspicion about what is true right now, and もしかして in particular is one of the most useful conversational openers in the language.

And もしもし on the phone is a doubled もし from a completely different root meaning "to say" — it is unrelated to any of this.

How do they sound in anime?

All four appear, but they cluster. ば shows up in declarations and dramatic lines because of its abstract, aphoristic feel:

やればできる。 — If you do it, you can do it. (you can do it if you try) いそがばまわれ。 — If you're in a hurry, go around. (haste makes waste — a proverb)

たら carries ordinary dialogue and threats alike, because it is about specific events:

けたら、わりだ。 — If we lose, it's over.

And もし at the front of any of them just flags "this is hypothetical" in advance. It is optional, it adds no grammar, and beginners tend to overuse it. もしあめったら is natural; あめったら on its own is equally correct and more common.

Common mistakes

  • と with a request or command. 時間じかんがあるとてください is wrong. と cannot be followed by anything a person chooses. Use たら.
  • ば with an action verb plus a request. 東京とうきょうけば連絡れんらくしてください sounds off; 東京とうきょうったら連絡れんらくしてください is right. ば prefers a state in front of a request.
  • Using なら for automatic results. はるになるならさくらく is wrong — nature is not responding to anything you said. That is と.
  • Thinking たら is only "if." Half the time it means "when": いえかえったら電話でんわします is a plan, not a doubt.
  • Overusing もし. It does not make a sentence more correct or more polite — it only marks the condition as hypothetical, and it sounds heavy when stacked on every conditional.
  • Using たら when the second clause comes first in time. 日本にほんったらカメラをいます means you buy it there. If you mean beforehand, you need なら.

The four at a glance

Feel Formation Command / request after it?
Automatic, always true Plain non-past + と No — never
Hypothetical, general -u → -eba Only if the first half is a state
たら Specific event, "if" or "when" Plain past + ら Yes
なら Picks up what was just said Noun / plain form + なら Yes

Practice

Answers are hidden — build yours first, then open. Questions 6 and 7 are a pair: only the conditional changes, and the camera moves with it.

1. Make the ば form of く.

Show answer

けば — the final く becomes け, then add ば. Group 1 verbs all work this way: む → めば, はなす → はなせば.

2. Make the たら form of べる.

Show answer

べたら — take the plain past べた and add ら. There are no exceptions to this rule, which is why たら is the safest conditional.

3. Something is wrong here: 時間じかんがあると、電話でんわしてください。

Show answer

時間じかんがあったら、電話でんわしてください — と claims the result is automatic, so nothing a person chooses can follow it. A request is a choice. たら takes requests without complaint.

4. Fill in: このボタンをす( )、みずます。

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— a machine doing the same thing every time is exactly what と is for. たら would also be understood, but と is what a manual or a sign would say.

5. A friend says 日本語にほんご勉強べんきょうしたいんです。Respond using なら.

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日本語にほんごなら、アニメで勉強べんきょうするのがたのしいですよ — なら attaches straight to the noun with no だ, and picks up what the other person just said. That "picking up" is the whole job of なら.

6. What does 日本にほんったら、カメラをいます mean about where the camera is bought?

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In Japan — たら puts the second event after the first on the timeline. You arrive, then you buy.

7. What does 日本にほんくなら、カメラをいます mean about where the camera is bought?

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Before leaving — なら only takes the trip as a premise, so the buying can come first. This is the pair to question 6: same words, opposite order of events.

8. Say "I should have studied more."

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もっと勉強べんきょうすればよかった — ば plus よかった is regret about something you did not do. する becomes すれば.

9. What is happening in まどひらけると、ゆきっていました?

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Discovery, not a condition — と with a past-tense main clause means "I did A, and found that B." Nothing is being supposed here; it already happened.

10. Which conditional should you use when you genuinely cannot decide?

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たら — it covers "if" and "when", accepts requests and commands, and has no conjugation exceptions. It is rarely the most elegant choice and almost never the wrong one.

FAQ

Is たら really always safe? Almost. The one place it loses is when the second clause happens before the first in time — that needs なら — and when you are stating a general law, where と sounds far more natural. Outside those two, たら will carry you.

Do I need もし? No. もし marks a condition as hypothetical, but the conditional ending already does the grammatical work. Use it for emphasis or to signal early in a long sentence that a supposition is coming, not as a required partner.

What is the difference between 〜たら and 〜とき? とき is "at the time when," and does not claim the event is uncertain: 日本にほんったとき、寿司すしべました = "when I went to Japan, I ate sushi" (it happened). たら carries a condition or a not-yet-happened event.

Why does ば exist if たら does more? Because ば is the conditional of general truths and fixed expressions, and because a huge amount of standard Japanese is built on it: 〜なければならない, 〜ばよかった, 〜ば〜ほど, and proverbs. You need to produce it even if たら covers your everyday sentences.

Can なら follow a verb? Yes — attach it to the plain form: くなら, べるなら, つかれているなら. It never takes だ, which makes it the only one of the four with nothing to conjugate.

Is 〜と also used for lists or quotes? It is, and those are different words that happen to share a shape: と also joins nouns ("and": パンとミルク) and marks quotations (〜といました). What comes before it tells you which one you are looking at — a noun means "and," a full clause in plain form means "if" or "when."

Vocabulary from this article

Tap the block to select all of it, then copy. In Anki: File → Import, note type Basic, separator Tab — the first column becomes the front, the second the back.

春	はる — spring
桜	さくら — cherry blossom
咲く	さく — to bloom
押す	おす — to push, to press
水	みず — water
曲がる	まがる — to turn
駅	えき — station
安い	やすい — cheap
練習	れんしゅう — practice
上手	じょうず — skilled, good at
雨	あめ — rain
帰る	かえる — to go home, to return
電話	でんわ — telephone, phone call
連絡	れんらく — contact, getting in touch
秋	あき — autumn
疲れる	つかれる — to get tired
休む	やすむ — to rest, to take a day off
窓	まど — window
開ける	あける — to open
雪	ゆき — snow
朝	あさ — morning
急ぐ	いそぐ — to hurry
回る	まわる — to go around
負ける	まける — to lose

I'm Yuuki, a Japanese teacher based in Tokyo. I've taught on italki as a Top 1% teacher and watched over 1,500 anime. In lessons this is the point where learners want a single rule, and the honest answer is that there isn't one — but there is a shortcut: use たら, and learn と and なら as the two specific jobs it cannot do.

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Sources: the author's own lessons and standard reference grammars.

More drills like the ones above, plus a timed JLPT-style mock test: Practice · N4

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