ならif that's so; if it's …
なら takes up what was just said or supposed, and answers it: "if you're going, then…". Nothing has to happen first, so the answer is often advice about what to do beforehand.
taking up a plan
If you're going to Hokkaido, I recommend a hotel near the sea.
if it's … you want
If you want somewhere quiet, the second floor of the library is a good choice.
supposing
If the prices are the same, I'll buy the larger one.
Verb, い-adjective
plain form + なら
行くなら, 行かないなら, 行ったなら, 高いなら
Noun, な-adjective
noun／な-adjective + なら
学生なら, 静かなら. No だ in between.
Taking up what someone said
Someone tells you a plan or a wish, and you say what you think of it: advice, an offer, a warning.
I am planning to drive to Kyoto next month.
If you are going by car, you should reserve parking early.
It can also take up what you see, or something you are only supposing.
If you can't decide, why not ask one of the staff?
If that doesn't suit you, another day is fine.
If it rains tomorrow, the game will be canceled.
なら or たら?
たら waits for the first half to happen. なら doesn't, so its second half can come before the first, and it is never "when" or "once".
Get in touch when you are in Tokyo.
First you arrive, then you get in touch.
If you are coming to Tokyo, get in touch.
The trip is only a plan. You get in touch before you come.
With a noun or a な-adjective the two meet: 雨だったら and 雨なら say the same thing.
Not said: 駅に
(Please call when you arrive at the station.)
This says "if you are going to arrive", as if the call came first.
Please call when you arrive at the station.
First you arrive, then you call, this once. たら takes the request.
After a noun: if it's … you mean
After a noun, なら takes up the thing someone asked about or wants. English often has no "if" for it.
Excuse me, is Ms. Tanaka here?
Ms. Tanaka? She's in the meeting room.
If you're looking for Japanese food, I recommend this restaurant.
It can also set one thing apart: this one yes, the others no. And 私なら is "if I were you".
I can't read kanji, but hiragana I can read.
If it were me, I wouldn't buy it.
The four ways to say "if"
Often more than one would fit, but each has its own job. One heater, four sentences, なら first.
If you are going to use the heating, please close the window first.
たらN4
The everyday "if" and "when": one thing happens, then the other. Of the four, the safe choice when you are not sure.
If it is cold, please turn on the heating.
とN4
For what follows by itself: how machines work, what the seasons bring, habits, directions. Never followed by a request, an invitation or a plan.
When you press this switch, the heating comes on.
ばN4
For what a result depends on: the "if" of advice and instructions. After something you do, a request takes たら, not ば.
You can turn on the heating if you press this button.
Close neighbours
それならN2
"In that case". It takes up everything the other person has just said.
Then let's look for somewhere else.
Check yourself
1Which one fits?
外国へ
Choose an answer to see why.
2Which one fits?
春に
Choose an answer to see why.
3Which one fits?
学生
Choose an answer to see why.
More detail
のなら, んだったら
のなら leans a little harder on "if that is really so". In conversation it is often んだったら.
If we're going to make a reservation, let's choose a window seat.
If you're going, I want to go too.
More sentences
If you're going to study in Japan, you should get insurance before you leave.
If you're taking part, please apply today. Applications close once the places are filled.
If you have been drinking, don't drive. If you are going to drive, don't drink.
A road-safety slogan everyone in Japan knows.