Because (から, ので)

We have already seen one way to express a reason or cause by using the te form.

電車でんしゃが遅おくれて、会社かいしゃに遅刻ちこくしました。

Because the train was delayed I was late for work.

Here we introduce the conjunctions から and ので which are very often translated as “because”. In fact, we’ve already met the latter as we will see shortly.

から

In English we can flip the sentence structure around with either “so” or “because”.

• I have no money so I cannot go on holiday.
• I cannot go on holiday because I have no money.

In Japanese we cannot do this without changing the structure substantially—the reason must come first. For verbs and i-adjectives we add から to the reason to create this grammar.

明日あしたは早はやく起おきるから、帰かえるよ。

I will wake up early tomorrow so I’m heading home.

このランプが とても安やすかったから、二ふたつ買かいました。

This lamp was very cheap so I bought two.

We can also use から with the polite ending.

お金かねがありませんから、旅行りょこうには行いけません。

Because I have no money I cannot go on holiday.

このゲームが楽たのしいですから、またやりたいです。

This game is fun so I want to play again.

から can also be used to give a reason in response to a question.

マイク	なんで疲つかれていますか。
Mike	Why are you tired?
由紀子ゆきこ	昨日きのう、夜よる１０時じまで仕事しごとをしていましたから。
Yukiko	Because yesterday I was working until 11pm.

With na-adjectives and nouns it requires the auxiliary verb (standard or polite).

親切しんせつだから、先生せんせいのクラスを受うけたい学生がくせいは多おおいです。

The teacher is kind so there are many students who want to take his class.

Note the position of the topic particle. A more direct translation might help with the grammar: “As for the students that want to take the teacher’s class, because he is kind, there are many.”

It can also be used as a conjunction in its own right.

祥子しょうこ	明日あしたはデパートのセールが始はじまるよ。
Shoko	The sales start at the department stores tomorrow.
健太けんた	だから、仕事しごとを休やすみたい。
Kenta	That’s why I want to take a holiday from work.

Using だから or ですから at the start of the sentence is a common way to begin an explanation.

から can also be used at the end of the sentence if we juggle the structure a little. In fact, we have already covered all the grammar required to do so.

絵里えりと話はなしたかったから、電話でんわしました。

I wanted to speak with Eri so I called her.

絵里えりに電話でんわした理由りゆうは、話はなしたかったからです。

The reason I called Eri is because I wanted to speak with her.

All we’re doing here is modifying the noun “reason”. Further the word “reason” can be replaced with の (the shorthand version of the word for the generic “something” こと) because it is obvious from the context you are giving a reason so we don’t need to explicitly use that word. Take the below, for instance:

コーヒーメーカーを買かったのは、朝あさにカフェに行いく時間じかんがないからです。

The reason I bought a coffee machine is because I don’t have time to go to the cafe in the morning.

This use of の can be somewhat confusing at first. It kind of acts as a kind of “joker” word becoming whatever is obvious from the context. In honesty, this structure is not heard all that often. In the majority of cases (certainly in conversation) you would simply say:

朝あさにカフェに行いく時間じかんがないから、コーヒーメーカーを買かいました。

I don’t have time to go to the cafe in the morning so I bought a coffee machine.

Nevertheless, changing from one structure to the other is a good way to test your understanding of the grammar.

ので

We have already learnt the grammar behind ので when こと was introduced to nominalise verbs. At the time it was noted that こと can be abbreviated to の for certain usages. で we already know can be used to express a reason. Combining these two pieces of grammar gives rise to ので.

体調たいちょうが良よくないことで、仕事しごとを休やすみました。

Because I didn’t feel good I took a break from work.

Literally: “By means of the thing that is not feeling good I took a break from work”.

Although the above is grammatically correct you would not likely hear it in conversation. Instead こと would be replaced with の to make a more natural sentence.

体調たいちょうが良よくないので、仕事しごとを休やすみました。

I didn’t feel good so I took a break from work.

洗濯機せんたくきが壊こわれたので、新あたらしいのを買かいに行いってきた。

The washing machine broke so I went to buy a new one.

Note how の is used to avoid repeating “washing machine”. It’s obvious from the context that you’re not going to go and buy a new toaster so the word “washing machine” doesn’t need to be repeated (in the same way I use “one” in the translation). の really is the lexical joker!

の may also be shortened to ん when used to mean ので in conversation.

明日あしたは試験しけんがあるんで、今日きょうは早はやく寝ねる。

I have an exam tomorrow so I’ll get to bed early today.

A critical rule to remember is how ので interacts with nouns and na-adjectives. Unlike から, which requires だ (e.g. 親切だから), ので requires な. This creates the incredibly common conjunction なので.

今日きょうは日曜日にちようびなので、銀行ぎんこうは休やすみです。

Today is Sunday so the bank is closed.

Like its counterpart から, ので can append itself to both the standard and polite forms of verbs and adjectives.

荷物にもつが多おおいですので、電車でんしゃじゃなくて、車くるまで行いきます。

I’ve got a lot of luggage so I’ll go by car not train.

テレビが二台にだいありますので、一台いちだい売うることを決きめました。

I’ve got two televisions so I’m going to sell one.

However, unlike から we cannot use ので in reply to a question.

マイク	なんで疲つかれていますか。
Mike	Why are you tired?
由紀子ゆきこ	昨日きのう、夜よる１０時じまで仕事しごとをしていましたので。(✗)
Yukiko	Because yesterday I was working until 11pm.

から vs. ので

Since both translate to “because” or “so”, how do you choose which one to use? The distinction lies in objectivity and politeness.

• から is subjective. It emphasizes the speaker’s personal reasoning, opinion, or volition. Because it focuses on personal justification, using it to excuse oneself can sometimes sound defensive or slightly forceful.
• ので is objective. It presents the reason as a natural, factual sequence of events. Consequently, it sounds softer, more objective, and significantly more polite.

As a general rule, ので is highly preferred in formal situations, business Japanese, when apologizing, or when making a polite request. Presenting your reason as an objective fact rather than a personal excuse is considered better etiquette.