Japanese Conditionals Explained

Ever feel like every time you want to say "if" or "when" in Japanese, you're faced with a half-dozen choices? You're not alone. The subtle differences between～たら (tara),～ば (ba),～なら (nara),～と (to), and～時とき(toki)are a common hurdle for learners.

Using the wrong one can make your sentences sound unnatural or, in some cases, change the meaning entirely. For example, some can be used for commands ("If you see him, tell him!") while others absolutely cannot.

This guide will clearly break down these five common phrases. We'll look at what each one really means, when to use it, and what restrictions to watch out for. By the end, you'll have a much clearer map for navigating these tricky but essential grammar points.

Key Differences at a Glance

Before we dive deep, here’s a high-level comparison. The first big split is betweenconditionals (if)andtemporals (when).～時とき(toki)is purely temporal, while the other four all carry some conditional "if" meaning.

The All-Rounder: ～たら (tara)

If you only remember one, make it～たら. It's the most versatile and common conditional in spoken Japanese. It's formed by adding～らto the past tense (たform) of a verb or adjective.

The core meaning is"After X happens (or if X happens), then Y."It focuses on the completion of the first action or state.

Use Case 1: Conditional ("If")

Used for a specific, one-time condition and its result.

• お金かねがあったら、旅行りょこうに行いきます。
• Okane gaattara, ryokou ni ikimasu.
• IfI have money, I will go on a trip.

Use Case 2: Temporal ("When")

Used when one action follows another in sequence.

• 家いえに着ついたら、電話でんわしてください。
• Ie nitsuitara, denwa shite kudasai.
• Whenyou get home, please call.

The Hypothetical: ～ば (ba)

～ばis more formal and is used forhypothetical or logical conditions. It's formed by changing the final～うsound of a verb to～えば(e.g.,買かう kau→買かえば kaeba) and～いfor adjectives to～ければ(e.g.,安やすい yasui→安やすければ yasukereba).

Think of it as "If X is true (as a general rule), then Y is the logical result."

• 安やすければ、買かいます。
• Yasukereba, kaimasu.
• Ifit's cheap, I'll buy it. (A general rule for my shopping.)

• 春はるになれば、花はなが咲さきます。
• Haru ni nareba, hana ga sakimasu.
• Ifit becomes spring, flowers bloom. (A logical, natural consequence.)

The Contextual "If": ～なら (nara)

～ならis the "contextual" conditional. It's used when you're making a statement or giving advicebased on information you just heard or a topic that was just raised.

Think of it as "If that's the case..." or "Speaking of X..."

Example Scenario:

You:「来週らいしゅう、日本にほんに行いきたいです。」 (Raishuu, Nihon ni ikitai desu.)
"I want to go to Japan next week."

Your Friend:「日本にほんに行いくなら、京都きょうとがおすすめです。」 (Nihon ni ikunara, Kyoto ga osusume desu.)
"Ifyou're going to Japan (since you mentioned it), I recommend Kyoto."

Your friend's advice is conditioned on the topic you brought up. Unlike～たら, the action in the～ならclause doesn't have to happen first. You can give advice about Kyoto before the person actually goes.

The Natural Consequence: ～と (to)

～とis the conditional of certainty. It's used whenY is a natural, habitual, or 100% certain result of X. It's like a scientific law or a machine's function.

It translates to "When X happens, Y always follows."

Use Case 1: Natural Law / Certainty

• 春はるになると、花はなが咲さきます。
• Haru ni naruto, hana ga sakimasu.
• Whenspring comes, flowers bloom. (Always happens.)

Use Case 2: Habitual Action

• このボタンを押おすと、ドアが開あきます。
• Kono botan o osuto, doa ga akimasu.
• Whenyou press this button, the door opens. (A reliable result.)

Like～ば,～とcannot be followed by commands, suggestions, or requests. It's a statement of fact, not a trigger for a personal action.

The Specific "When": ～時とき(toki)

Finally,～時とき(toki). This one is simple:it is not a conditional "if."It is a purely temporal marker that means "when" or "at the time of."

The trickiest part of～時ときis that the tense of the verb before it changes the meaning.

Example 1: Dictionary Form (Before)

• 日本にほんへ行いく時とき、パスポートを買かいました。
• Nihon eiku toki, pasupooto o kaimashita.
• WhenI went to Japan, I bought a passport. (Meaning: I bought the passport before I left.)

Example 2: Past Tense (After/During)

• 日本にほんへ行いった時とき、お土産みやげを買かいました。
• Nihon eitta toki, omiyage o kaimashita.
• WhenI went to Japan, I bought souvenirs. (Meaning: I bought the souvenirs after I arrived in Japan.)

Common Mistakes to Avoid

1. Using～とor～ばfor Commands:

   Remember, only～たら,～なら, and～時ときcan naturally be followed by commands or requests.
   Incorrect:駅えきに着つくと、電話でんわしてください。
   Correct:駅えきに着ついたら、電話でんわしてください。

2. Confusing～たらand～時とき:

   ～たらimplies a sequence ("after you arrive...").～時ときimplies a point in time ("at the time of arriving...").
   着ついたら電話でんわして。(Call me after you've arrived.)
   着つく時とき電話でんわして。(Call me as you are arriving.)

3. Using～ならfor General Hypotheticals:

   ～ならis for contextual assumptions, not general "if" statements.
   Incorrect:明日あした晴はれるなら、ピクニックに行いきます。
   Correct:明日あした晴はれたら、ピクニックに行いきます。

Frequently Asked Questions

Can ～たら (tara) and ～ば (ba) be interchanged?

Sometimes, but they have different nuances.～たらis better for specific, one-time events (especially with commands), while～ばis better for general truths or logical, hypothetical conditions. For example, "If you press this, it works" (general) is better with～ば. "If it rains, I'll stay home" (specific plan) is better with～たら.

What's the simplest rule for these conditionals?

When in doubt,～たらis often the safestand most versatile choice for "if" or "when" in daily, casual conversation. It can cover conditions, sequences of events, and be used with commands or suggestions.

Does ～時とき(toki) ever mean 'if'?

No.～時とき(toki)strictly means "when" or "at the time of." It is a temporal marker, not a conditional one. It doesn't carry the "if" (hypothetical) nuance that～たら,～ば, and～ならdo.