How to Say ‘Why’ in Japanese

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It is widely known that Japan has a culture of utmost courtesy and politeness.

So, although your curiosity may push you to ask ‘why, why, why?’, it is important not to be overly intrusive when speaking with your Japanese acquaintances.

The standard way to say ‘why’ in Japanese is naze (なぜ).

In this post, we will look at naze and other main terms for how to say ‘why’ in Japanese (yes, there are multiple)!

We will discuss how to use such terms appropriately and more.

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Common ways to say ‘why’ in Japanese

Naze (desu ka)


Why (standard, polite)

Naze (なぜ), sometimes written 何故, is the standard way of asking ‘why’ in Japanese.

Reflective of how we use ‘why’ in English, you can use naze it on its own to simply ask ‘why?’. Alternatively, you can place it at the beginning of a sentence to ask questions such as ‘why do you…?’ Or ‘why is it…?’.

Naze can be used in a range of different situations, from casual to formal. In casual situations, you may stick to plain (dictionary) form.

In formal situations, use the masu-form for verbs or simply add desu ka (ですか) at the end to sound extra polite. 


Naze sou omoimasu ka?
Why do you think so?

A woman questioning how to say why in japanese on a white background holding a large red question mark in her hand

Doushite (desu ka)


How come

Doushite (どうして) is very similar to naze, although it can be considered more casual sounding. For reference, it is often compared to ‘how come?’ in English.

In terms of use, it can be used in the same way as naze.



Why (casual)

Nande (何で / なんで) is another relatively informal way of asking ‘why’ in Japanese. It is commonly used in familiar settings such as with family and friends. Therefore, if you are a fan of anime you may recognise this term!

Nan (何) or nani means ‘what’ and the particle de (で) means ‘by/with’, indicating means of action. If you were to literally translate nande it would be ‘by what (means)?’. This double meaning can cause confusion, so it’s important to be aware of the context in which nande is used to decipher the proper nuance.

Below is an example of how nande may be interpreted in different ways.


Nande kita no?
Why did you come here? / How (by what means) did you come here? 

A young woman peering over her glasses, looking confused, saying "why" in Japanese.

Nan no tame ni


For what reason

Nan no tame ni (何のために / なんのために) is of course another way to ask ‘why’ in Japanese.

Tame means ‘aim’ or ‘purpose’ and therefore this phrase is useful when asking someone the reason behind their actions. 


Nan no tame ni nihon ni itta no?
Why / for what reason did you go to Japan?

More ‘why’ related phrases

Naze nara


Why (explanation)

Technically, naze nara (なぜなら) is a formal way of expressing ‘because’. However, I mention it as it is a term often used in response to a ‘why’ question. In English, we may say ‘if you want to know why…’

It is good to be aware of this phrase so you can understand when someone is asking naze? vs explaining themselves using naze nara…

⚪︎⚪︎ masen ka


Why don’t we ⚪︎⚪︎

As you know, Japanese culture holds great importance in being polite. Part of being polite is to speak in a way which is not too forward. Therefore, the more indirect you can be in asking a question, the more polite you sound. We also do this in English by asking negative questions. 

To form a negative question in Japanese, simply use the negative form of the verb and add a question marker at the end.

The question markers are: no (の) for plain form verbs (casual) and ka (か) for masu form verbs (polite). You should also use a higher inflection in your voice towards the end of the sentence to emphasise that you are asking a question.


Kouen ni isshoni ikimasen ka?
Why don’t we go to the park together?

‘Why’ in non-standard Japanese

Standard Japanese is what is taught in schools and used in official settings. This is the Japanese we are used to hearing, and if you visit Tokyo it is the main version of the language that you will hear.

However, the further you venture out from Tokyo, the more you will notice slight variations, whether it be in accent or terminology.

Let’s look at a couple of ways to ask ‘why’ other Japanese dialects! 



Why is that / what the heck ?! (Osaka dialect)

A man in a plaid shirt asking 'why' in Japanese with his hands outstretched looking confused.

This term originates from Osaka in the Kansai region. If you are an anime or manga fan, you have very likely heard nandeyanen (なんでやねん) being thrown around! It is generally used as an exclamation in times of surprise, such as ‘what the heck’. 

  • As you can see, the utterance contains nande, which we know means ‘why’.
  • The ya (や) is particular to Osaka dialect and is their version of da (だ) -which is the plain form of desu (です). 
  • Where we say no da (のだ) in standard dialect, they say nen (ねん) in Osaka, and is really just added for emphasis. 

It must be said that it is definitely not the most polite of phrases. So I would suggest sticking to using this phrase strictly with close friends/family. It will definitely get a laugh out of them!



Why (Hokkaido dialect)

Nashite (なして) is actually ‘why’ in Hokkaido dialect! It is a casual term and if you were to hear someone utter nashite you can safely assume that they are from Hokkaido.

Nani yue ni


Why (old fashioned)

Nani yue ni (何故に / なにゆえに) is surely not a word you will be using or even hearing in daily conversation. That being said, it does mean ‘why’ so it can’t be left out of this lesson!

Although you may not use it, you may hear it being said on TV or in movies, particularly period dramas set in old Japan.

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Hannah Stafford

Hannah is a half Irish/half Japanese girl living in Ireland. Her love for Japan and the Japanese language led her to studying languages and translation in university where she specialised in Japanese. She spent a year studying abroad at Rikkyo University in Tokyo. In her free time, Hannah enjoys using her sewing machine to upcycle clothes and create new pieces!

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