Translation guide
The English verb "know" covers several distinct concepts in Japanese, including factual knowledge, familiarity with people/places, understanding, and ability. Japanese uses different verbs and constructions depending on what is known and how the knowledge was acquired.
Knowing a fact, piece of information, or answer to a question.
The most common way to say you know a fact. Literally 'have come to know and am in that state'. Use this for knowing information, answers, news, etc.
彼の電話番号を知っていますか。
Do you know his phone number?
そのニュースはもう知っている。
I already know that news.
The dictionary form meaning 'to come to know, to find out'. Use this for the moment of learning something, not for ongoing knowledge. Often used in past tense 知った (found out) or negative 知らない (don't know).
Do not use 知る in present tense to mean 'I know'. Use 知っている instead.
Polite/honorific way to ask 'do you know?'. Used in formal situations or when speaking to superiors.
田中様をご存知ですか。
Do you know Mr./Ms. Tanaka? (polite)
Being acquainted with someone or something through experience.
Also used for knowing people, places, books, etc. through experience or acquaintance.
彼女を知っていますか。
Do you know her?
この辺りをよく知っている。
I know this area well.
Knowing the meaning, reason, or nature of something; understanding deeply.
Means 'to understand, to comprehend'. Often a better translation for 'know' when referring to understanding a concept, reason, or language.
Knowing how to do something; having a skill.
Pattern meaning 'can do, know how to do'. Attach to dictionary form of verb.
彼はピアノを弾くことができる。
He knows how to play the piano.
日本語を話すことができますか。
Do you know how to speak Japanese?
Knowing something through personal experience; recognizing something as familiar.
Used for knowing a taste, feeling, or experience.
この味を知っている。
I know this taste.
Literally 'have experience'. Used to say you have experienced something.
Being aware that something is the case; knowing about a situation.
General awareness of a fact or situation.
彼が来ることを知っていた。
I knew he was coming.
知っている is for factual knowledge or acquaintance. わかる is for understanding, comprehension, or figuring out. If you can replace 'know' with 'understand', わかる is often better.
The plain form 知る means 'to come to know' or 'to find out', not 'to know' as a state. Always use 知っている for ongoing knowledge. 知らない is the negative form for 'don't know'.
I found out the truth yesterday.
彼が結婚したことを知らなかった。
I didn't know he got married.
Noun meaning 'acquaintance'. Used to describe someone you know but are not close to.
彼は仕事の知り合いです。
He's a work acquaintance.
Formal expression meaning 'to be acquainted with someone' (have met them).
彼とは面識がありません。
I'm not acquainted with him.
その言葉の意味がわかりますか。
Do you know the meaning of that word?
なぜ彼が怒っているのかわからない。
I don't know why he's angry.
More formal/literary word for 'understand, comprehend'. Often used for deeper understanding of complex topics.
彼の理論を完全に理解している。
I fully understand his theory.
Means 'to know well, to be aware of, to understand the rules/etiquette'. Often used in formal contexts.
茶道の作法を心得ている。
I know the etiquette of tea ceremony.
Potential form of verbs, meaning 'can do'. More casual than ことができる.
彼はピアノが弾ける。
He can play the piano.
Can also be used for knowing a method or way, often with やり方 (way of doing).
駅までの行き方を知っていますか。
Do you know how to get to the station?
海外で働いた経験がありますか。
Do you have experience working abroad?
Means 'to recognize, to look familiar'. Used for visual recognition.
あの人に見覚えがある。
I know that person from somewhere (I've seen them before).
Means 'to notice, to become aware'. Often used for realizing something you didn't know before.
間違いに気づかなかった。
I didn't know it was a mistake (I didn't notice the mistake).
Formal word for 'know, be aware, consent'. Often used in business to acknowledge information.
その件は承知しております。
I am aware of that matter. (formal)