Differences among -たら, なら, -と, -んだったら, -ば, etc


The Japanese language has a lot of patterns for "if" clauses. What are the
differences among the following patterns and how do we choose to use one over
the others?:

  * 行くと
  * 行ったら
  * 行くなら
  * 行けば
  * 行くんだったら
  * 行くのなら
  * 行くとしたら
  * 行くことになったら
  * 行くならば

p/s: Please add any other additional "if" patterns




## と, ば

The main clause must be a constant non-volitional reaction to the conditional
clause unless the conditional clause shows state or if the subjects of the two
clauses differ.

> お金を入れてボタンを押すと、切符が出ます。  
>  'When you put in money and press the button, a ticket will come out.'

> 春になると、観光客が増えます。  
>  'When spring arrives, tourists increase.'

> 早く行かないと、遅刻します。  
>  'If you don't leave soon, you'll be late.'

> × お家に帰ると、連絡してください。  
>  お家に帰ったら、連絡してください。  
>  'Please contact me once you return home.'

> × パリに行くと、凱旋門【がいせんもん】にも行ってみたい。  
>  パリに行ったら、凱旋門にも行ってみたい。  
>  'When I go to Paris, I'd like to see the Arc de Triomphe.'

> × 帰宅すれば、必ずお風呂に入りなさい。  
>  帰宅したら、必ずお風呂に入りなさい。  
>  'When you get home, be absolutely sure to take a bath.'

> わからないことがあったら、いつでも聞いてください。  
>  わからないことがあれば、いつでも聞いてください。  
>  'If there's something you don't understand, ask me anytime.'

> 父が許してくれれば、彼と結婚するつもりです。  
>  'If my father lets me, I intend to marry him.'

## と

The conditional clause must be non-past.

> × 窓を開けたと、冷たい風が入ってきた。  
>  窓を開けると、冷たい風が入ってきた。  
>  'When I opened the window, a cool breeze came in.'

> × デパートに行ったと、チョコレートが山積みになっていた。  
>  デパートに行くと、チョコレートが山積みになっていた。  
>  'When I went to the department store, I found mountains of chocolate piled
> up.'

## ～ば

  1. The condition must have not happened yet.

> 明日もし雨が降れば、どうしますか。  
>  明日もし雨が降ったら、どうしますか。  
>  × 明日もし雨が降ると、どうしますか。  
>  'If it rains tomorrow, what should we do?'

> × 注射を打ってもらえば、すぐ直りました。  
>  注射を打ってもらったら、すぐ直りました。  
>  'When I had the injection, I got better right away.'

  2. ～ば is the most common conditional when the emphasis is on what is required to bring about a _desired_ result. Thus, use ～ば when the focus of the sentence is on the conditional clause:

> どうすれば、東大に入学できますか。  
>  What should I do to get into Tokyo University?

Consequently, when the succeeding clause describes an undesirable result, ～ば
sounds unnatural:

> ？ 徹夜すれば、体調が悪くなります。

> Instead: 徹夜すると、体調が悪くなります。  
>  If you stay up all night, you'll damage your health. (～たら is also OK)

But when the preceding clause uses さえ to show the minimal criteria needed to
achieve a result, ～ば is your only option:

> お金さえ払えば、だれでも入会できる。  
>  So long as they pay, anyone can join. (Neither ～たら nor ～と work here.)

  3. Use when talking about what _would_ happen if something (which is not actually true) were true:

> あと1000円あれば、このコートを買えるのに。  
>  If I had 1,000 yen more, I could buy this coat.

> あのとき右に曲がれば、どうなっただろう。  
>  If I had turned right back then, I wonder what would have happened.

Note that the tense of the following clause shows whether you're speculating
on the past or non-past, and that past-tense verbs are allowed in this case.

## ～たら

  1. Use when expressing a one-off (as opposed to constant or general) dependency. _Like_ ～ば, this can be used when it is unknown whether the preceding clause will come true:

> 雨が降ったら、試合は中止です。  
>  If it rains, the game will be called off. (～ば is also OK)

_Unlike_ ～ば, ～たら can be used when it is a known fact that the preceding clause
will come true:

> 午後になったら、散歩に行きましょう。  
>  In the afternoon ("When it becomes the afternoon"), let's go for a walk.
> (～ば is not OK)

  2. Use when the following clause shows intent, desire, or is a command/request:

> 食事ができたら、呼んでください。  
>  When the food's ready, call me. (～ば is not OK unless the sentence is one of
> the exceptional cases mentioned above)

  3. Use like ～と to show a sequential, cause-and-effect relationship between the two clauses:

> 田中さんにメールを送ったら、すぐ返事が来ました。  
>  When I texted Ms. Tanaka, I got a reply right away. (～と is also OK, but not
> ～ば)

  4. ～たら can also take the polite form (along with ～と), but this is usually heard only in formal settings:

> ご感想がございましたら、ぜひお寄せ下さい。  
>  If you have any feedback, please send it to us.

## ～なら

  1. Use when you are drawing out a conclusion based on the first clause:

> A: スーパーに行ってくるよ。  
>  I'm going to the supermarket.
>
> B: スーパーに行くのなら、しょうゆを買ってきて。  
>  If you're going to the supermarket, bring back some soy sauce.

> 大学院に進むなら、この本を読みなさい。  
>  If you're going to go to graduate school, read this book.

  2. Use when you need the freedom to have the succeeding clause happen before the preceding clause. This is something ～と, ～ば, and ～たら _cannot do_ :

> 旅行に行ったのなら、写真を見せてください。  
>  If you went on vacation, please show me your photos. (A→B)

> 旅行に行くのなら、カメラを持っていくといいですよ。  
>  If you're going on vacation, you should take a camera. (B→A)

> 飲んだら、乗るな。乗るなら、飲むな。  
>  If you've had a drink, don't drive. (A→B) If you're going to drive, don't
> drink. (B→A)

Do note that the rule of drawing out a conclusion based on the first clause
still applies in these examples.

  3. Alternate forms:

  * なら will sometimes have a の or ん in front of it; the meaning does not change.
  * In speech, のなら sometimes becomes のだったら (or んだったら), again with no change in meaning.
  * I believe ならば is a more formal, written version of なら, but I don't have a solid reference on this.

## ～としたら

This is one of many forms of ～とする. The ～とする form is used when setting up a
supposition as the basis for succeeding statements:

> 有名人にばったり会うとしたら、どうする？  
>  Supposing you happen to meet someone famous, what would you do?

> 新しい車を買ったとしても、それで幸せにはならないと思う。  
>  Even supposing I were to buy a new car, I don't think that would make me
> happy.

> じゃあ、犯人はこの部屋に入ったとしよう。目的はなんだったんだろうね。  
>  So let's suppose the criminal entered this room. What do you imagine he was
> after?

## ～ことになったら

This is a combination of the ～ことになる form ("end up", "turn out to") and the ～たら
conditional:

> 結婚することになったら、結婚式で歌っていただけませんか。  
>  If it so happens that I get married, would you please sing for me at the
> wedding?

> 海外に行くことになったら、手紙を毎週書いて送るよ。  
>  If I end up going overseas, I'll write you every week.

## Variances among dialects

As if this wasn't complicated enough, a study done in 1989 by Shinji Sanada
showed that Tokyo speakers and Osaka speakers sometimes differ greatly in
their use of conditionals. A few examples:

> もっと早く｛起きると／起きれば／起きたら｝よかった。  
>  I should have woken up earlier.

  * Tokyo: 4% と; **94% ば** ; 2% たら
  * Osaka: 0% と; 20% ば; **78% たら**

> 右に｛行くと／行けば／行ったら｝、ポストが見えます。  
>  If you turn right, you can see a mailbox.

  * Tokyo: **75% と** ; 16% ば; 8% たら
  * Osaka: 4% と; 13% ば; **83% たら**

* * *

Source for ～と, ～ば, ～たら, ～なら, and dialectical variance study:
[初級を教える人のための日本語文法ハンドブック
(2000)](https://www.amazon.co.jp/%E5%88%9D%E7%B4%9A%E3%82%92%E6%95%99%E3%81%88%E3%82%8B%E4%BA%BA%E3%81%AE%E3%81%9F%E3%82%81%E3%81%AE%E6%97%A5%E6%9C%AC%E8%AA%9E%E6%96%87%E6%B3%95%E3%83%8F%E3%83%B3%E3%83%89%E3%83%96%E3%83%83%E3%82%AF-%E5%BA%B5-%E5%8A%9F%E9%9B%84/dp/4883191559)

Source for ～としたら and ～ことになったら: personal experience




## と, ば

The main clause must be a constant non-volitional reaction to the conditional
clause unless the conditional clause shows state or if the subjects of the two
clauses differ.

> お金を入れてボタンを押すと、切符が出ます。  
>  'When you put in money and press the button, a ticket will come out.'

> 春になると、観光客が増えます。  
>  'When spring arrives, tourists increase.'

> 早く行かないと、遅刻します。  
>  'If you don't leave soon, you'll be late.'

> × お家に帰ると、連絡してください。  
>  お家に帰ったら、連絡してください。  
>  'Please contact me once you return home.'

> × パリに行くと、凱旋門【がいせんもん】にも行ってみたい。  
>  パリに行ったら、凱旋門にも行ってみたい。  
>  'When I go to Paris, I'd like to see the Arc de Triomphe.'

> × 帰宅すれば、必ずお風呂に入りなさい。  
>  帰宅したら、必ずお風呂に入りなさい。  
>  'When you get home, be absolutely sure to take a bath.'

> わからないことがあったら、いつでも聞いてください。  
>  わからないことがあれば、いつでも聞いてください。  
>  'If there's something you don't understand, ask me anytime.'

> 父が許してくれれば、彼と結婚するつもりです。  
>  'If my father lets me, I intend to marry him.'

## と

The conditional clause must be non-past.

> × 窓を開けたと、冷たい風が入ってきた。  
>  窓を開けると、冷たい風が入ってきた。  
>  'When I opened the window, a cool breeze came in.'

> × デパートに行ったと、チョコレートが山積みになっていた。  
>  デパートに行くと、チョコレートが山積みになっていた。  
>  'When I went to the department store, I found mountains of chocolate piled
> up.'

## ～ば

  1. The condition must have not happened yet.

> 明日もし雨が降れば、どうしますか。  
>  明日もし雨が降ったら、どうしますか。  
>  × 明日もし雨が降ると、どうしますか。  
>  'If it rains tomorrow, what should we do?'

> × 注射を打ってもらえば、すぐ直りました。  
>  注射を打ってもらったら、すぐ直りました。  
>  'When I had the injection, I got better right away.'

  2. ～ば is the most common conditional when the emphasis is on what is required to bring about a _desired_ result. Thus, use ～ば when the focus of the sentence is on the conditional clause:

> どうすれば、東大に入学できますか。  
>  What should I do to get into Tokyo University?

Consequently, when the succeeding clause describes an undesirable result, ～ば
sounds unnatural:

> ？ 徹夜すれば、体調が悪くなります。

> Instead: 徹夜すると、体調が悪くなります。  
>  If you stay up all night, you'll damage your health. (～たら is also OK)

But when the preceding clause uses さえ to show the minimal criteria needed to
achieve a result, ～ば is your only option:

> お金さえ払えば、だれでも入会できる。  
>  So long as they pay, anyone can join. (Neither ～たら nor ～と work here.)

  3. Use when talking about what _would_ happen if something (which is not actually true) were true:

> あと1000円あれば、このコートを買えるのに。  
>  If I had 1,000 yen more, I could buy this coat.

> あのとき右に曲がれば、どうなっただろう。  
>  If I had turned right back then, I wonder what would have happened.

Note that the tense of the following clause shows whether you're speculating
on the past or non-past, and that past-tense verbs are allowed in this case.

## ～たら

  1. Use when expressing a one-off (as opposed to constant or general) dependency. _Like_ ～ば, this can be used when it is unknown whether the preceding clause will come true:

> 雨が降ったら、試合は中止です。  
>  If it rains, the game will be called off. (～ば is also OK)

_Unlike_ ～ば, ～たら can be used when it is a known fact that the preceding clause
will come true:

> 午後になったら、散歩に行きましょう。  
>  In the afternoon ("When it becomes the afternoon"), let's go for a walk.
> (～ば is not OK)

  2. Use when the following clause shows intent, desire, or is a command/request:

> 食事ができたら、呼んでください。  
>  When the food's ready, call me. (～ば is not OK unless the sentence is one of
> the exceptional cases mentioned above)

  3. Use like ～と to show a sequential, cause-and-effect relationship between the two clauses:

> 田中さんにメールを送ったら、すぐ返事が来ました。  
>  When I texted Ms. Tanaka, I got a reply right away. (～と is also OK, but not
> ～ば)

  4. ～たら can also take the polite form (along with ～と), but this is usually heard only in formal settings:

> ご感想がございましたら、ぜひお寄せ下さい。  
>  If you have any feedback, please send it to us.

## ～なら

  1. Use when you are drawing out a conclusion based on the first clause:

> A: スーパーに行ってくるよ。  
>  I'm going to the supermarket.
>
> B: スーパーに行くのなら、しょうゆを買ってきて。  
>  If you're going to the supermarket, bring back some soy sauce.

> 大学院に進むなら、この本を読みなさい。  
>  If you're going to go to graduate school, read this book.

  2. Use when you need the freedom to have the succeeding clause happen before the preceding clause. This is something ～と, ～ば, and ～たら _cannot do_ :

> 旅行に行ったのなら、写真を見せてください。  
>  If you went on vacation, please show me your photos. (A→B)

> 旅行に行くのなら、カメラを持っていくといいですよ。  
>  If you're going on vacation, you should take a camera. (B→A)

> 飲んだら、乗るな。乗るなら、飲むな。  
>  If you've had a drink, don't drive. (A→B) If you're going to drive, don't
> drink. (B→A)

Do note that the rule of drawing out a conclusion based on the first clause
still applies in these examples.

  3. Alternate forms:

  * なら will sometimes have a の or ん in front of it; the meaning does not change.
  * In speech, のなら sometimes becomes のだったら (or んだったら), again with no change in meaning.
  * I believe ならば is a more formal, written version of なら, but I don't have a solid reference on this.

## ～としたら

This is one of many forms of ～とする. The ～とする form is used when setting up a
supposition as the basis for succeeding statements:

> 有名人にばったり会うとしたら、どうする？  
>  Supposing you happen to meet someone famous, what would you do?

> 新しい車を買ったとしても、それで幸せにはならないと思う。  
>  Even supposing I were to buy a new car, I don't think that would make me
> happy.

> じゃあ、犯人はこの部屋に入ったとしよう。目的はなんだったんだろうね。  
>  So let's suppose the criminal entered this room. What do you imagine he was
> after?

## ～ことになったら

This is a combination of the ～ことになる form ("end up", "turn out to") and the ～たら
conditional:

> 結婚することになったら、結婚式で歌っていただけませんか。  
>  If it so happens that I get married, would you please sing for me at the
> wedding?

> 海外に行くことになったら、手紙を毎週書いて送るよ。  
>  If I end up going overseas, I'll write you every week.

## Variances among dialects

As if this wasn't complicated enough, a study done in 1989 by Shinji Sanada
showed that Tokyo speakers and Osaka speakers sometimes differ greatly in
their use of conditionals. A few examples:

> もっと早く｛起きると／起きれば／起きたら｝よかった。  
>  I should have woken up earlier.

  * Tokyo: 4% と; **94% ば** ; 2% たら
  * Osaka: 0% と; 20% ば; **78% たら**

> 右に｛行くと／行けば／行ったら｝、ポストが見えます。  
>  If you turn right, you can see a mailbox.

  * Tokyo: **75% と** ; 16% ば; 8% たら
  * Osaka: 4% と; 13% ば; **83% たら**

* * *

Source for ～と, ～ば, ～たら, ～なら, and dialectical variance study:
[初級を教える人のための日本語文法ハンドブック
(2000)](https://www.amazon.co.jp/%E5%88%9D%E7%B4%9A%E3%82%92%E6%95%99%E3%81%88%E3%82%8B%E4%BA%BA%E3%81%AE%E3%81%9F%E3%82%81%E3%81%AE%E6%97%A5%E6%9C%AC%E8%AA%9E%E6%96%87%E6%B3%95%E3%83%8F%E3%83%B3%E3%83%89%E3%83%96%E3%83%83%E3%82%AF-%E5%BA%B5-%E5%8A%9F%E9%9B%84/dp/4883191559)

Source for ～としたら and ～ことになったら: personal experience

