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.
Do you know his phone number?
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.
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.
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.
Knowing something through personal experience; recognizing something as familiar.
Used for knowing a taste, feeling, or experience.
Being aware that something is the case; knowing about a situation.
General awareness of a fact or situation.
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.
I know the answer. (I have the information)
昨日、真実を知った。
I found out the truth yesterday.
I didn't know he got married.
Do you know her?
I know this area well.
Noun meaning 'acquaintance'. Used to describe someone you know but are not close to.
He's a work acquaintance.
Formal expression meaning 'to be acquainted with someone' (have met them).
I'm not acquainted with him.
Do you know the meaning of that word?
I don't know why he's angry.
More formal/literary word for 'understand, comprehend'. Often used for deeper understanding of complex topics.
I fully understand his theory.
Means 'to know well, to be aware of, to understand the rules/etiquette'. Often used in formal contexts.
I know the etiquette of tea ceremony.
He knows how to play the piano.
Do you know how to speak Japanese?
Potential form of verbs, meaning 'can do'. More casual than ことができる.
He can play the piano.
Can also be used for knowing a method or way, often with やり方 (way of doing).
Do you know how to get to the station?
I know this taste.
Literally 'have experience'. Used to say you have experienced something.
Do you have experience working abroad?
Means 'to recognize, to look familiar'. Used for visual recognition.
I know that person from somewhere (I've seen them before).
I knew he was coming.
Means 'to notice, to become aware'. Often used for realizing something you didn't know before.
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.
I am aware of that matter. (formal)
答えがわかる。
I understand the answer. (I comprehend it)
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'.