なぜ

Why

なぜ私わたしの家いえに来きたんですか？

Why did you come to my house?

Explanation

「なぜ」 means 'why' and asks for a cause or reason. Of the three 'why' words it is the most formal and most written: 「なぜ空は青いのか」 (Why is the sky blue?). It is common in papers, news, meetings and discussions. In everyday chat it sounds a bit stiff, like a cross-examination.

Mixed up with

The three 'why' words compared:

「なぜ」: the most formal and rational; for writing, news and getting to the root of something.

「どうして」: the most all-round; fine in conversation and writing, and often shows concern or puzzlement: 「どうして来なかったの？」 (Why didn't you come?)

「なんで」: the most casual, among people who are close; easily sounds impatient or accusing: 「なんでだよ！」

Examples

ここがこうなっているのはなぜですか？
Why is this like this right here?
なぜここに猫ねこがいるの？
Why is there a cat here?
なぜ雪ゆきは白しろいの？
Why is snow white?
なぜあの海うみは汚きたないのですか。
Why is that sea dirty?
この猫ねこは何故なぜ毎日まいにちここに来くるのだろうか。
I wonder why this cat comes here every day.
なぜ水みずを買かったんですか？
Why did you buy water?
なぜ、彼かれは面白おもしろいの？
Why is he funny?
野菜やさいが嫌きらいなのはなぜですか？
Why do you dislike vegetables?
なぜこれは冷つめたいのですか？
Why is this cold?
先生せんせい：「なぜ休やすむんですか？」生徒せいと：「お腹なかが痛いたいからです。」
Teacher: 'Why are you taking the day off?' Student: 'Because my stomach hurts.'
学校がっこうに行いくのはなぜ？
Why go to school?
なぜこれが良いいのか教おしえます。
I'll tell you why this is good.
お風呂ふろに入はいらないのはなぜ？
Why don't you take baths?
なぜコーヒーを飲のまなかったの？
Why didn't you drink coffee?
なぜサクラさんは、ヨウコさんと会あうの？
Why is Sakura meeting with Yoko?
シン：「なぜ手紙てがみを書かいているの？」ユウ：「彼女かのじょが好すきだからだよ。」
Shin: 'Why are you writing a letter?' Yu: 'Because I like her.'
なぜ鯉こいを見みに行いくの？
Why are you going to see the koi?