Chapter 10 — Conditional Forms: と, ば, たら, なら

English has one word for "if." Japanese has four conditional forms, and they are not interchangeable. Each one encodes a different relationship between the condition and the result — automatic consequence, hypothetical possibility, completed-action trigger, or response to new information. Choosing the wrong conditional is not a grammatical error in most cases, but it makes the sentence sound unnatural or changes the meaning in ways the speaker did not intend.

This chapter covers all four forms: と, ば, たら, and なら. It also introduces もし (an optional word that signals a conditional is coming) and ても/でも ("even if"). By the end of this chapter, you will be able to parse any conditional sentence in Japanese and understand why the speaker chose that particular form.

The conditional system is widely considered one of the hardest topics in Japanese for learners. The difficulty is real, but it is manageable if you understand the core logic of each form rather than trying to memorize a list of rules. Each form has a personality, and once you grasp that personality, the specific usage rules follow naturally.

10.1 と — Natural / Automatic Consequence

The conditional と expresses a natural, automatic, or inevitable consequence. If A happens, B naturally follows. There is no uncertainty, no choice, no human will involved in the connection between condition and result. It is used for physical laws, habitual patterns, machine operations, and directions.

Formation

Attach と directly to the plain non-past form of the verb, adjective, or copula. The verb before と is always in the non-past form, even when describing past habitual actions.

Examples: natural consequences

このボタンを 押すと、ドアが 開きます。 "If you press this button, the door opens."

春に なると、桜が 咲きます。 "When spring comes, the cherry blossoms bloom."

たくさん 食べると、おなかが いっぱいに なります。 "If you eat a lot, you get full."

右に 曲がると、駅が あります。 "If you turn right, there is a station."

氷は 暖かく なると、水に なります。 "When ice gets warm, it becomes water."

Examples: habitual patterns

と is also used for habitual, repeated patterns — things that always happen the same way.

毎朝 六時に なると、目が さめます。 "Every morning, when it becomes six o'clock, I wake up."

冬に なると、この 町は 雪が たくさん 降ります。 "When winter comes, this town gets a lot of snow."

あの 人は お酒を 飲むと、よく 歌います。 "When that person drinks alcohol, he often sings."

Examples: discoveries — past tense with と

When と is used with a past-tense main clause, it describes a discovery: "when I did A, I found B."

窓を 開けると、きれいな 山が 見えました。 "When I opened the window, I could see a beautiful mountain."

家に 帰ると、 猫が ソファで 寝ていました。 "When I got home, the cat was sleeping on the sofa."

箱を 開けると、中に 手紙が 入っていました。 "When I opened the box, there was a letter inside."

This discovery use of と is very common in narratives and is a distinctive feature of Japanese storytelling.

The critical restriction: no requests, commands, or intentions in the main clause

This is the most important rule for と. The main clause (the result) cannot express a request, command, invitation, intention, or permission. These involve human will, and と describes automatic, will-free consequences.

✗ 駅に 着くと、電話してください。 ✗ 暇だと、遊びに 来ませんか。 ✗ 安いと、買おう。

None of these are grammatical with と. The result clauses involve a request (ください), an invitation (来ませんか), and an intention (買おう). For these, use たら or ば instead.

○ 駅に 着いたら、電話してください。 ○ 暇だったら、遊びに 来ませんか。 ○ 安かったら、買おう。

10.2 ば — Hypothetical Condition

The conditional ば expresses a hypothetical condition — "if A were the case, then B." It presents the condition as something that may or may not be true, and asks the listener to consider the consequence. ば has a somewhat formal, literary feel and is particularly common in proverbs, advice, and general statements.

Formation

The formation of ば differs by word type.

五段 verbs: Change the final -u vowel to -e and add ば.

Notice this is the same え-row as the imperative form (Chapter 6) and the potential form stem (Chapter 1). The ば is simply added to this base.

一段 verbs: Drop る and add れば.

Irregular verbs:

い-adjectives: Drop い and add ければ.

Note that いい uses its alternate stem よ: いい → よければ.

な-adjectives: Stem + であれば. In casual speech, stem + なら can also be used.

静かであれば — "if it is quiet" 元気であれば — "if one is healthy"

Noun + copula: noun + であれば.

学生であれば — "if one is a student" 日曜日であれば — "if it is Sunday"

Negative ば-form: For verbs, use the ない-form and treat ない as an い-adjective: drop い, add ければ.

行かない → 行かなければ — "if one does not go" 食べない → 食べなければ — "if one does not eat"

You already know this pattern from なければならない ("must"), which literally means "if one does not [do it], it won't do."

Examples

安ければ、買います。 "If it's cheap, I'll buy it."

天気が よければ、散歩に 行きましょう。 "If the weather is good, let's go for a walk."

もっと 勉強すれば、上手に なりますよ。 "If you study more, you'll get better."

時間が あれば、ぜひ 来てください。 "If you have time, please come by all means."

薬を 飲めば、すぐ よくなります。 "If you take the medicine, you'll get better right away."

早く 寝れば、朝 起きられます。 "If you go to bed early, you can get up in the morning."

ば and requests

Unlike と, ば can be used when the main clause is a suggestion or general advice. However, it is slightly awkward with direct requests (ください). For direct requests, たら is preferred.

○ 安ければ、買いましょう。 (suggestion — natural with ば) ○ 聞けば、わかりますよ。 (advice — natural with ば) △ 着いたら、電話してください。 (direct request — たら is more natural)

Proverbs with ば

ば is the conditional of choice in many set phrases and proverbs:

失敗は 成功の もと。 転ばなければ、分からない。 "Failure is the foundation of success. If you don't fall, you won't understand."

住めば 都。 "If you live there, it's the capital." (Meaning: anywhere feels like home once you get used to it.)

10.3 たら — "When / If (Completed)"

たら is the most versatile conditional in Japanese. It can be used in almost any situation where と, ば, or なら would work, and it has the fewest restrictions. For this reason, many textbooks recommend it as the "default" conditional when in doubt. While this advice is not wrong, each conditional has contexts where it sounds more natural, and learning when to use each one is worth the effort.

Formation

たら is formed by adding ら to the た-form. Since you already know how to make the た-form for all verb types, adjectives, and copulas, formation is straightforward.

Verbs: た-form + ら

い-adjectives: Drop い, add かったら.

Again, いい uses its alternate stem: いい → よかったら.

な-adjectives: Stem + だったら.

静かだったら — "if it's quiet" 暇だったら — "if (you're) free"

Nouns: Noun + だったら.

日曜日だったら — "if it's Sunday" 雨だったら — "if it's rain (raining)"

Negative: ない → なかったら.

行かなかったら — "if (you) don't go" 高くなかったら — "if it's not expensive"

Core meaning: "after A is completed, B"

The fundamental logic of たら is temporal sequence with completion: once A is finished or realized, B happens or becomes relevant. This "completed" nuance comes from the た-form at its base.

駅に 着いたら、電話してください。 "When you arrive at the station, please call."

The condition 着いたら implies completion — after your arrival is a fact, then call. This makes たら natural for sequential events.

Examples: hypothetical conditions

安かったら、買います。 "If it's cheap, I'll buy it."

暇だったら、映画を 見に 行きませんか。 "If you're free, would you like to go see a movie?"

薬を 飲んだら、よくなりますよ。 "If you take the medicine, you'll get better."

百万円 あったら、何を しますか。 "If you had a million yen, what would you do?"

天気が よかったら、公園に 行きましょう。 "If the weather is good, let's go to the park."

Examples: temporal "when"

When the speaker expects the condition to actually happen, たら functions as "when" rather than "if."

家に 帰ったら、すぐ シャワーを 浴びます。 "When I get home, I'll take a shower right away."

三十歳に なったら、結婚したいです。 "When I turn thirty, I want to get married."

宿題が 終わったら、ゲームを してもいいですよ。 "When you finish your homework, you can play games."

Examples: unexpected discovery (past tense)

Like と, たら can describe an unexpected result when the main clause is past tense.

朝 起きたら、雪が 降っていました。 "When I woke up in the morning, it was snowing."

家に 帰ったら、友達が 来ていました。 "When I got home, my friend had come over."

ドアを 開けたら、猫が 入って来ました。 "When I opened the door, a cat came in."

たら and requests

Unlike と (which prohibits requests) and ば (which is somewhat awkward with them), たら works perfectly with requests, commands, invitations, and intentions.

着いたら、電話してください。 — "When you arrive, please call." (request) よかったら、一緒に 行きませんか。 — "If it's okay with you, won't you come along?" (invitation) 安かったら、買おう。 — "If it's cheap, let's buy it." (intention)

This flexibility is why たら is called the most versatile conditional.

10.4 なら — "If What You Say Is True"

なら is the most distinctive of the four conditionals. It responds to information the speaker has just received from the listener or from the situation. The English equivalent is roughly "if (what you say about A is true), then B." なら takes the listener's statement or a known situation as its starting point and builds a response on it.

Formation

なら attaches to the plain form. For nouns and な-adjectives, だ before なら is optional.

The distinctive feature: responding to information

なら is used when the speaker is responding to something the listener said or implied. This gives it a conversational, reactive quality that the other conditionals lack.

A: 明日 東京に 行きます。 B: 東京に 行くなら、この 店に 行ってみてください。おいしいですよ。 A: "I'm going to Tokyo tomorrow." B: "If you're going to Tokyo, try this restaurant. It's delicious."

Speaker B picks up A's statement ("I'm going to Tokyo") and uses it as a condition to make a recommendation. This is the classic なら pattern.

A: 日本語を 勉強したいんですが。 B: 日本語を 勉強するなら、この 本が いいですよ。 A: "I'd like to study Japanese." B: "If you're going to study Japanese, this book is good."

A: パソコンが こわれました。 B: パソコンを 買うなら、あの 店が 安いですよ。 A: "My computer broke." B: "If you're going to buy a computer, that store is cheap."

Notice in the last example that B inferred from A's situation (broken computer) that A might buy a new one, and used なら to frame the advice. なら does not require the listener to have stated the condition explicitly — it can be inferred.

Chronological flexibility

A unique feature of なら is that the main clause can describe something that happens before the condition. With と, ば, and たら, the result always comes after the condition chronologically. なら has no such restriction.

東京に 行くなら、この お土産を 持って行ってください。 "If you're going to Tokyo, please take this souvenir with you."

The action "take this souvenir" happens before or at the same time as "going to Tokyo," not after. This is natural with なら but would be awkward or impossible with the other conditionals.

図書館に 行くなら、この 本を 返してきてください。 "If you're going to the library, please return this book (for me)."

Again, the returning of the book happens during the trip, not as a consequence of completing the trip.

Examples

日本の 食べ物なら、寿司が 一番 好きです。 "If we're talking about Japanese food, I like sushi the best."

旅行するなら、京都が いいと 思います。 "If you're going to travel, I think Kyoto is good."

そんなに 疲れているなら、今日は 早く 寝た ほうが いいですよ。 "If you're that tired, you should go to bed early today."

この 問題が わからないなら、先生に 聞いてみたほうが いいです。 "If you don't understand this problem, you should try asking the teacher."

10.5 Contrastive Analysis

This section compares all four conditionals through parallel examples, highlighting where they overlap and where they diverge.

"If it's cheap, I'll buy it."

安いと、買います。 — Natural/automatic: "whenever it's cheap, I buy it" (habitual pattern). 安ければ、買います。 — Hypothetical: "if it happens to be cheap, I'll buy it." 安かったら、買います。 — Completed: "if it turns out to be cheap, I'll buy it." 安いなら、買います。 — Responsive: "if (you're telling me) it's cheap, then I'll buy it."

All four are grammatical, but each creates a slightly different nuance.

"If you don't understand, please ask."

✗ わからないと、聞いてください。 — Ungrammatical. と cannot precede requests. △ わからなければ、聞いてください。 — Slightly stiff but acceptable. ○ わからなかったら、聞いてください。 — Natural and common. ○ わからないなら、聞いてください。 — Natural, with a responsive nuance.

"When spring comes, flowers bloom."

○ 春に なると、花が 咲きます。 — Natural. This is an automatic, recurring event. △ 春に なれば、花が 咲きます。 — Acceptable but sounds like a proverb or general truth. △ 春に なったら、花が 咲きます。 — Acceptable but implies a specific future spring. ✗ 春に なるなら、花が 咲きます。 — Unnatural. Nobody is telling you spring will come.

Summary table

The ○ marks indicate where each form is natural and commonly used. △ indicates possible but not the most natural choice. ✗ indicates ungrammatical or unnatural.

The following matrix provides a more detailed feature-by-feature comparison of all four conditional forms:

Conditional Comparison Matrix

✓ = natural · △ = possible with restrictions · ✗ = unnatural

Quick guide:

• と → automatic/inevitable results (laws of nature, habits)
• ば → general conditions, advice, hypothetical
• たら → most versatile; specific/one-time events; "when/if"
• なら → "if it's the case that..."; topical condition

10.6 もし — Optional Intensifier

もし means "if" and can be placed at the beginning of a conditional sentence as an optional signal that a conditional is coming. It is not required and adds no grammatical information, but it helps the listener prepare to process a conditional structure.

もし is compatible with ば, たら, and なら. It is not used with と (because と expresses certainty, and もし emphasizes uncertainty or hypotheticality).

もし 時間が あれば、手伝ってください。 "If you have time, please help."

もし 明日 雨が 降ったら、家に います。 "If it rains tomorrow, I'll stay home."

もし よかったら、一緒に 行きませんか。 "If it's okay (with you), would you like to go together?"

もし 百万円 あったら、何を しますか。 "If you had a million yen, what would you do?"

もし is especially common before counterfactual hypotheticals — situations that are unlikely or contrary to reality.

もし わたしが 鳥だったら、空を 飛びたいです。 "If I were a bird, I would want to fly in the sky."

10.7 ても / でも — "Even If"

ても and でも express concession: "even if A, B" — meaning that B holds true regardless of whether A is the case. The condition does not change the outcome.

Formation

Verbs: て-form + も

い-adjectives: Drop い, add くても.

な-adjectives: Stem + でも.

静かでも — "even if it's quiet" 好きでも — "even if you like it"

Nouns: Noun + でも.

日曜日でも — "even if it's Sunday" 学生でも — "even if one is a student"

Negative: ない → なくても.

行かなくても — "even if you don't go" 高くなくても — "even if it's not expensive"

Examples

薬を 飲んでも、よくなりませんでした。 "Even though I took the medicine, I didn't get better."

たくさん 食べても、太りません。 "Even if I eat a lot, I don't gain weight."

高くても、買いたいです。 "Even if it's expensive, I want to buy it."

雨が 降っても、サッカーを します。 "Even if it rains, we'll play soccer."

何回 聞いても、わかりません。 "No matter how many times I listen, I don't understand."

だれに 聞いても、同じ ことを 言います。 "No matter who you ask, they say the same thing."

Interrogative + ても — "no matter wh-"

When ても is combined with an interrogative word (何, だれ, どこ, いつ, etc.), it creates a "no matter..." expression.

何を 食べても、おいしいです。 — "No matter what I eat, it's delicious." だれが 来ても、大丈夫です。 — "No matter who comes, it's fine." どこに 行っても、日本語を 使います。 — "No matter where I go, I use Japanese." いつ 来ても、いいですよ。 — "No matter when you come, it's fine." どんなに 勉強しても、漢字を おぼえられません。 — "No matter how much I study, I can't memorize the kanji."

This pattern is extremely common and useful.

10.8 Reading Passage

お悩み 相談

相談： わたしは 来年 大学を 卒業します。日本語が 好きで、大学で 四年間 勉強しました。卒業したら、日本で 働きたいと 思っています。でも、日本で 仕事を 見つけるのは むずかしいと 聞きました。日本語が 上手でも、外国人が 日本の 会社に 入るのは 大変だそうです。どうしたら いいですか。（二十二歳、男）

回答： お手紙 ありがとうございます。日本で 働きたいなら、まず、自分が 何を したいか よく 考えた ほうが いいと 思います。

日本語が 上手ければ、仕事は きっと 見つかります。四年間 日本語を 勉強したなら、かなり 話せるはずですよ。

もし 日本の 会社で 働くなら、日本語だけではなく、日本の ビジネスの やり方も 勉強する ことを おすすめします。日本の 会社に 入ると、敬語を たくさん 使います。敬語が わからなかったら、仕事が 大変に なるかもしれません。

それから、最近は 外国人を 採用する 会社が 増えているそうです。あきらめなければ、きっと いい 仕事が 見つかるはずです。がんばってください。

Translation

Question: I will graduate from university next year. I like Japanese and studied it for four years at university. After I graduate, I want to work in Japan. But I heard it is difficult to find a job in Japan. Even if your Japanese is good, it is apparently tough for a foreigner to enter a Japanese company. What should I do? (Twenty-two years old, male.)

Answer: Thank you for your letter. If you want to work in Japan, first, I think it would be good to think carefully about what you want to do.

If your Japanese is good, you will surely find a job. If you studied Japanese for four years, you should be able to speak quite well.

If you are going to work at a Japanese company, I recommend studying not only Japanese but also how Japanese business is done. When you enter a Japanese company, you use a lot of keigo. If you don't understand keigo, work might become difficult.

Also, apparently the number of companies hiring foreigners has been increasing recently. If you don't give up, you should surely find a good job. Good luck.

Reading Passage 2 — 日本旅行の　アドバイス

Read the following passage, which gives travel advice about Japan using all four conditional forms.

日本に 旅行するなら、いくつか 知っておいた ほうが いい ことが あります。

まず、京都に 行くなら、秋が おすすめです。十一月に なると、木の 葉が 赤や 黄色に なって、とても きれいです。でも、秋の 京都は 人が 多いので、ホテルは 早く 予約しておかなければ なりません。もし 安く 泊まりたかったら、京都の 少し 外の 町に 泊まると いいですよ。電車で 二十分も 行けば、静かで 安い 旅館が 見つかります。

天気に ついても 気を つけてください。六月に 日本に 来たら、毎日 雨が 降るかもしれません。六月は 梅雨の 季節だからです。かさを 持っていかなければ、こまる ことに なります。もし 雨が 降ったら、美術館や 博物館に 行くと いいです。東京なら、室内で 楽しめる 場所が たくさん あります。

食べ物に ついて 言えば、日本では どこに 行っても、おいしい 物が 食べられます。もし 何を 食べるか 迷ったら、その 町の 名物を 食べてみてください。大阪に 行ったら、たこやきを 食べなければ なりません。北海道なら、ラーメンが 有名です。

日本語が 話せなくても、大丈夫です。大きい 駅に 行けば、英語の 案内が あります。でも、「すみません」と「ありがとう」が 言えれば、旅行は もっと 楽しくなりますよ。

Translation

If you are going to travel to Japan, there are a few things it is good to know in advance.

First, if you are going to Kyoto, autumn is recommended. When November comes, the leaves of the trees turn red and yellow and it is very beautiful. But since autumn Kyoto has many people, you must reserve a hotel early. If you want to stay cheaply, it is good to stay in a town slightly outside of Kyoto. If you go just twenty minutes by train, you can find quiet and inexpensive inns.

Please also be careful about the weather. If you come to Japan in June, it may rain every day. This is because June is the rainy season. If you do not bring an umbrella, you will be in trouble. If it rains, it is good to go to art museums or museums. If it is Tokyo, there are many places you can enjoy indoors.

Speaking of food, no matter where you go in Japan, you can eat delicious things. If you are unsure what to eat, try eating the local specialty of that town. If you go to Osaka, you must eat takoyaki. If it is Hokkaido, ramen is famous.

Even if you cannot speak Japanese, it is fine. If you go to a large station, there is English-language guidance. But if you can say "sumimasen" and "arigatou," your trip will become much more enjoyable.

Notes on the passage

おすすめ — "recommendation." From すすめる（勧める）, "to recommend."

梅雨（つゆ）— "rainy season." A period of continuous rain in June across much of Japan.

博物館（はくぶつかん）— "museum." 美術館 is "art museum."

名物（めいぶつ）— "local specialty, famous product." Every region in Japan has signature foods.

迷う（まよう）— "to be lost, to be unsure, to hesitate." 迷ったら = "if you are unsure."

Note the conditional variety: The passage uses なら for responding to travel plans, と for natural consequences, たら for hypothetical situations, and ば for general conditions. Each is chosen to match the nuance described in this chapter.

10.9 Vocabulary List