Questions and Demonstratives
Asking Why in Formal and Objective Contexts
The question word なぜ is used to ask why or request a logical reason for an event or situation. It carries a formal, objective tone and is most common in written language, news reports, and formal speeches. Because it can sound stiff and interrogative, it is generally avoided in everyday casual conversation.
01Main Functions
Asking for Logical Reasons
Used to seek a factual or logical explanation for a situation rather than asking about personal emotional motives.
なぜ機械が止まったのですか。
Why did the machine stop?
Seeking Formal Explanations
Used in formal situations, such as interviews or serious meetings, when requesting an explanation from someone.
なぜ会議に遅れたのですか。
Why were (you) late to the meeting?
Written Objective Inquiries
Commonly seen in essays, articles, and tests where an objective or academic tone is required.
なぜこの問題が起きるのか。
Why does this problem occur?
02Sentence Pattern
なぜ + verb + ますか
なぜ日本へ行きますか。
Why will (you) go to Japan?
Pairs with a standard polite verb ending to ask for a logical reason.
なぜ + verb + ましたか
なぜ昨日学校を休みましたか。
Why were (you) absent from school yesterday?
Pairs with a polite past-tense verb to ask why a past event happened.
なぜ + verb + のですか
なぜ日本語を勉強するのですか。
Why do (you) study Japanese?
The explanatory ending のですか emphasizes that the speaker is actively requesting a logical explanation.
なぜ + verb + んですか
なぜいつも遅れるんですか。
Why are (you) always late?
The ending んですか is slightly more spoken than のですか, but when paired with なぜ, the question still retains a formal or serious tone.
なぜ + i-adjective + ですか
なぜこのパソコンは高いですか。
Why is this computer expensive?
Pairs with a polite i-adjective predicate to seek an objective reason for a described state.
なぜ + na-adjective + ですか
なぜこの町は静かですか。
Why is this town quiet?
Pairs with a polite na-adjective predicate. The na-adjective attaches without な before です.
なぜ + noun + ですか
なぜ今日は休みですか。
Why is today a day off?
Pairs with a polite noun predicate to ask the reason behind a fact or identity.
03Example Sentences
なぜ日本へ行きますか。
Why will (you) go to Japan?
A straightforward polite question asking for a logical reason.
なぜ昨日学校を休みましたか。
Why were (you) absent from school yesterday?
Asks for the reason behind a past action in a formal context.
なぜ日本語を勉強するのですか。
Why do (you) study Japanese?
The explanatory ending のですか emphasizes that a formal, logical explanation is being requested.
なぜ早く帰るんですか。
Why will (you) go home early?
The ending んですか is slightly more spoken, but paired with なぜ, the question still retains a formal or serious tone.
なぜこのパソコンは高いですか。
Why is this computer expensive?
Seeks an objective reason for a state described by an i-adjective.
なぜ昨日は忙しかったのですか。
Why were (you) busy yesterday?
Pairs with a past-tense i-adjective and the explanatory のですか.
なぜこの町は静かですか。
Why is this town quiet?
Asks for the factual reason behind a na-adjective state.
なぜ今日は休みですか。
Why is today a day off?
Pairs with a polite noun predicate to ask the reason behind a fact.
なぜ肉を食べないのですか。
Why do (you) not eat meat?
Asks for a reason behind a negative action or habit using the explanatory ending.
なぜ電車が止まったのか。
Why did the train stop?
A written-style objective inquiry ending in the plain form and the question particle か.
なぜ一人なのですか。
Why are (you) alone?
When using a noun with the explanatory のですか, な must be added after the noun.
なぜ宿題をしませんでしたか。
Why did (you) not do (your) homework?
A formal, direct inquiry about a failure to perform a required action.
なぜ空は青いですか。
Why is the sky blue?
An objective question asking for a scientific or logical fact.
なぜカメラを買ったのですか。
Why did (you) buy a camera?
Asking for the reason behind a completed past action using the explanatory tone.
04Comparisons
なぜ vs. どうして
どうして is the most versatile and common word for why in everyday spoken Japanese. It can ask for factual reasons, but also explores personal motives, emotions, or purpose. なぜ is strictly formal, logical, and objective, making it better suited for serious interviews, news reports, or written essays.
なぜこの問題が起きるのか。
Why does this problem occur?
どうして泣いているのですか。
Why are (you) crying?
なぜ vs. なんで
なんで is the most casual word for why and is heavily used in relaxed daily conversations with friends and family. なぜ is on the opposite end of the formality spectrum; using なぜ with friends can sound overly stiff, cold, or interrogative.
なんで昨日来なかったの。
Why didn't (you) come yesterday?
なぜ会議に遅れたのですか。
Why were (you) late to the meeting?
なぜ vs. なに
While both are basic question words, なぜ asks for the reason or cause, whereas なに asks for the object or content. They take different grammatical roles in a sentence.
なぜ買いましたか。
Why did (you) buy (it)?
なにを買いましたか。
What did (you) buy?
05Nuance and Usage
なぜ is the most formal and objective way to ask why in Japanese. It is used to seek logical, factual explanations for situations, rather than exploring personal motives or emotional reasoning. Because of its serious tone, you will frequently hear it in news broadcasts, academic contexts, formal speeches, and business environments.
While it can be used in formal speech, such as interviews or serious meetings, なぜ is heavily associated with written Japanese. In essays, reports, and articles, it sets a professional and objective tone. When speaking casually with friends or family, using なぜ can sound unnatural, stiff, or even like a police interrogation.
When asking someone directly for a reason in a formal setting, it is very common to pair なぜ with the explanatory endings のですか or んですか. These endings emphasize that you are actively requesting a logical explanation. If you just use the standard ますか or ですか, the question can sometimes feel slightly more distant or purely factual.
06Core Explanation
The question word なぜ is used to ask why or request a logical reason for an event or situation.
The question word なぜ is the formal and objective way to ask why or request a reason in Japanese. It is used when the speaker is looking for a factual, logical explanation rather than exploring a personal or emotional motive.
Because of its objective tone, なぜ belongs primarily to a formal or written register. You will frequently encounter it in news broadcasts, essays, academic writing, and formal public speaking. When addressing an audience or investigating a factual matter, なぜ provides a serious and respectful distance.
When asking a direct question to a listener in a formal setting, なぜ is typically paired with polite sentence endings such as ですか or ますか. To emphasize that you are actively seeking an explanation, it is very common to pair なぜ with the explanatory ending のですか or its spoken equivalent んですか.
It is helpful to compare なぜ with other words for why that you will encounter, such as どうして and なんで. どうして is the standard, versatile word for why used in everyday spoken Japanese, while なんで is highly casual. なぜ is strictly more formal, stiff, and logical than both of these alternatives.
A common mistake for learners is using なぜ in casual everyday conversations with friends or family. Because of its stiff and objective nature, using なぜ in relaxed settings can sound unnatural, cold, or even like a police interrogation. For everyday spoken situations, it is much more natural to use どうして or なんで.
07Common Mistakes
Wrong
なぜ昨日来なかったの。
Correct
どうして昨日来なかったの。
Why: When speaking casually with friends or family, using なぜ sounds far too stiff, cold, or interrogative. For everyday casual speech, use どうして or なんで instead.
Wrong
なぜ遅れました。
Correct
なぜ遅れましたか。
Why: なぜ asks a question, so the sentence must end with a question marker like か, especially in the formal contexts where なぜ is naturally used.
Wrong
なぜを買いますか。
Correct
なにを買いますか。
Why: なぜ means why and cannot be marked as a direct object with the particle を. To ask what someone will buy, use なに.
Wrong
なぜ学校は休みのですか。
Correct
なぜ学校は休みなのですか。
Why: When pairing a noun or a na-adjective with the explanatory ending のですか, you must insert な before の.
Wrong
なぜだですか。
Correct
なぜですか。
Why: The plain copula だ cannot be attached directly to the polite copula です. To politely ask why is it, just use なぜですか.
Wrong
映画を見ますかなぜ。
Correct
なぜ映画を見ますか。
Why: In Japanese, question words like なぜ typically appear before the verb or at the beginning of the clause, not tagged onto the very end after the question particle か.
08Questions
Can I use なぜ when talking to my friends?
It is grammatically understood, but it sounds very stiff, cold, or like an interrogation. For casual, everyday conversation with friends, it is much more natural to use どうして or なんで.
What is the exact difference between なぜ and どうして?
どうして is the most versatile word for why in spoken Japanese and can be used to ask for reasons, emotional motives, or purpose. なぜ is strictly more formal, objective, and logical, making it better suited for written texts, news broadcasts, and serious formal situations.
Why do I often see なぜ paired with のですか?
The ending のですか explicitly marks that the speaker is seeking an explanation. Since なぜ asks for a logical reason, they pair together very naturally in formal speech to show that you are actively expecting an answer.
09Mini Practice
- 01
(In a formal interview) Why do (you) study Japanese? （ ）日本語を勉強するのですか。
- 02
Why did the train stop? なぜ電車が（ ）。
- 03
(Texting a close friend) なぜ昨日来なかったの。
- 04
Why will (you) go to Japan?
Tap the pieces in the correct order.
- 05
Why is today a day off? なぜ今日は休み（ ）。
- 06
Why do (you) not eat meat? なぜ肉を食べない（ ）。
- 07
(A news reporter investigating an incident) なぜ機械が止まったのですか。
- 08
Why is the sky blue?
Tap the pieces in the correct order.
Summary
Learner Summary
- なぜ means why and is used to ask for a logical or objective reason.
- It is the most formal way to ask why in Japanese, setting a serious and professional tone.
- You will frequently encounter it in written language, essays, news reports, and formal speeches.
- Because it can sound overly stiff or interrogative, it is usually avoided in casual, everyday conversation with friends.
- It is often paired with the explanatory endings のですか or んですか to emphasize that a logical explanation is being requested.
10Study Map
Study Info
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