What does Desu Mean and How to Use it

“です” (desu) is probably one of the very first words any Japanese beginner encounters. This famous and mischievous sentence ender is rarely missed in any Japanese conversations and textbooks. Many may think です is simply the equivalent of “to be” and that was it. But in fact, です can be applied in different contexts where the meaning of the verb “to be” didn’t make any sense.

So in this article, I will try to cover all the uses of です a Japanese learner should know. From its meaning to various usages in different sentence types, you’ll understand this word in a more comprehensive way.

Let’s begin!

What does “desu” mean?

In Japanese, the word です takes on several meanings. It could be translated as “to be,” “is,” and the different conjugations and forms of this verb. です plays the role of a copula verb, that role is to connect the subject with its complement/predicate. But です has other uses as well. 

Maybe, you might have seen this word attached to the end of many sentences, playing the role of “formality or politeness indicator“. 

In some cases, です can transform a “casual” sentence or expression into a polite one. However, you have to be very careful, if used in the wrong way it could lose its meaning.

How to Use Desu?

Positive Form 

Noun + です

This is one of the first grammatical structures that we can find in the initial lessons of the Japanese language. The noun connected to the word です creates a simple, affirmative sentence in the present tense. The phrase “N + desu” also has an explanatory or confirmatory function. In this case, we could say that です works as  “is”, “am”, “are”, etc. 

ナナです。

I’m Nana. 

 

パスタです。 

It’s pasta.

 

私たちは同僚です。

Watashitachi wa dōyō desu.

We are coworkers.

Adjectives + です

As my grammar teacher used to say,  “adjectives add flavor to the language“. An adjective modifies the noun, describing its qualities and characteristics. When we create a sentence using  Japanese adjectives, the structure is similar to the first pattern we saw earlier. We just need to add the word です after the adjective and we’re ready and good to go. In Japanese, there are 2 types of adjectives:  い (i) adjectives and な (na) adjectives. 

Let’s see some examples of how です interacts with each one of them.

い Adjective + です 

このソースは辛いです。  

Kono sōsu wa karai desu. 

This sauce is hot/spicy. 

Usually,  in a context where the noun is known,  it is omitted in the conversation. Let’s say that it is implied that we are talking about the “sauce“, we could perfectly say “辛いです”, and it is grammatically correct. Even if we just say “辛い”, the meaning of what we said is pretty clear. Here, the word です works as a polite attribute, giving a certain level of formality to the expression.  Speaking or writing with some level of politeness is something valued in Japanese culture. 

な Adjective + です 

彼は親切です。 

Kare wa shinsetsu desu. 

He is kind. 

We can see that な adjectives and nouns have similar interactions with the copula です. If we are in a casual conversation,  between friends or close relatives, the word です could be replaced by the word だ.  In this type of context です and だ would be equivalent. 

Note: Although it is true that in some cases です and だ work as variants of the same word, this is not always the case. For example, in a sentence that includes an い adjective, the word だ  is not a substitute for the word です. In fact, if we add だ after an い adjective, it would be grammatically incorrect. Like the previous example,  if we want to transform an い adjective + です structure into casual/informal, we just have to remove the word です from the equation. 

Negative Form 

Previously, we talked about です and its role as a politeness marker. In the Japanese language, there are different levels of formality. According to the hierarchical position of the person you’re speaking with, you need to adjust the type of expressions you use. 

So far, we have seen affirmative sentences and their formal and casual counterparts. Now,  we will see different ways of constructing the same negative sentence with different levels of formality. 

Let’s observe how in some of the following sentences です changes its form completely —  while in others it stays the same. But its role is different.

These sentences all mean the same, “she is not Japanese”.  The level of politeness goes in descending order, one — being the most polite.

彼女は日本人ではありません。

Kanojo wa nihonjin dewa arimasen. 

 

彼女は日本人ではないです。 

Kanojo wa nihonjin dewa nai desu. 

 

彼女は日本人じ ゃありません。  

Kanojo wa nihonjin jārimasen. 

 

彼女は日本人じゃないです。 

Kanojo wa nihonjin janai desu. 

 

彼女は日本人じゃない。 

Kanojo wa nihonjin janai. 

While it is true that so many variants of the same sentence can be overwhelming, it is good to emphasize that it is not necessary to learn them all at once. Learning the fundamentals is more than enough to communicate in different types of scenarios without the risk of being rude or impolite. 

In this article, we will focus on the most common ones. 

The basic structure for a negative Japanese sentence is constructed with the following “formula”  →  N1 は N2 じゃ ありません. 

じゃ ありません is the negative form of です and we use it to build negative sentences in the present tense. We can use this syntax to turn both nouns and な adjectives into their negative form.

Noun + じゃ ありません 

これはパスタじゃありません。 

Kore wa pasuta ja arimasen. 

This is not pasta. 

 な Adjectives  + じゃ ありません 

彼は有名じゃありません。 

Kare wa yūmei ja arimasen. 

He is not famous. 

 *For nouns and な adjectives,  we can increase or decrease the level of politeness,  by applying the same rules used in the previous examples. 

い Adjectives → ~くない  + です 

い adjectives can be “conjugated” into different forms and tenses. 

To turn a positive い adjective structure into a negative one, we replace the い with the conjugation〜くない.  We add ですat the end for politeness.  

このケーキは甘くないです。 

Kono kēki wa amakunai desu. 

This cake is not sweet. 

Negative Form | Verbs + です 

In the plain form of Japanese verbs, we use the ーない conjugation to turn it into a negative. Here, the word です serves to add a polite tone to the sentence as well.

私は肉を食べないです。 

Watashi wa niku wo tabenai desu. 

I don’t eat meat. 

Now that we have seen the different uses of です in the present tense, let’s see how it works in the past tense. 

Past Tense – Affirmative でした  |  〜かったです 

Just like in the present tense structures, to build a sentence in the past tense, we have to take into consideration the rules and differences of each grammatical construction.

If it’s a noun or a な adjective compound, です becomes でした. 

Noun + でした

私の前のパソコンは便利でした。 

Watashi no mae no pasokon wa benri deshita. 

My previous laptop was convenient. 

 な Adjectives  + でした 

あの場所はきれいでした。 

Ano basho wa kirei deshita. 

That place was beautiful. 

In the case of い adjectives, the い is removed and the suffix かった is added to turn it into the past tense, then we add です as a politeness marker. 

い Adjectives + かった 

その映画は悲しかったです。 

Sono eiga wa kanashikattadesu. 

That movie was sad. 

Past Tense – Negative  

For nouns and な adjectives, we use the same rules as the negative present tense, we just need to add でした after じゃ ありません. 

Noun + じゃ ありませんでした

私の前のパソコンは便利じゃ ありませんでした。 

Watashi no mae no pasokon wa benri jaarimasen deshita. 

My previous laptop was not convenient. 

な Adjectives + じゃ ありませんでした

あの場所はきれいじゃありませんでした。 

Ano basho wa kirei ja arimasen deshita. 

That place was not beautiful. 

い Adjectives → くない + かった 

In the negative form of い adjectives, ~くない, we apply the same rule as its positive counterpart. For the past tense, we remove the い and add the suffix かった. 

このケーキは甘くなかったです。 

Kono kēki wa amakunakatta desu. 

This cake was not sweet. 

In the case of the past negative of verbs ( plain form), the pattern is the same as the past negative of い adjectives. 

私は 酒を飲まなかったです。   

Watashi wa sake wo nomanakatta desu. 

I didn’t drink sake. 

～んです (n desu) 

 The purpose of this syntax is to emphasize a specific aspect of the conversation, and also to give a sense of fluency and naturality to the dialogue. It has the same meaning as the word です and is placed at the end of a sentence too— preceded by the plain form of a verb, adjective, or noun. 

い Adjectives + んです 

今日は寒いんです。 

Kyō wa samuindesu. 

It’s cold today. 

 な Adjectives  + んです 

その携帯は便利なんです。 

Sono keitai wa benrina ndesu. 

That mobile phone is convenient. 

Nouns + んです 

あやかはとても有名なんです。 

Ayaka wa totemo yūmeina ndesu. 

Ayaka is very famous. 

Verbs + んです 

今週の金曜日はアムステルダムへ旅行するんです。 

Konshū noKin’yōbi wa Amusuterudamu he ryokō surundesu. 

I’m traveling to Amsterdam on Friday. 

This structure is extremely versatile. I recommend the article “The Meaning of ‘-N Desu’ in Japanese”, written by Namiko Abe, to understand more deeply its many uses and underlying meanings. 

Desu vs Da

Both です and だ share the same meaning. When it comes to nouns or Na adjectives, both function as a variant of the other, だ  being the casual version of です. However, as we have seen so far, there are situations where desu becomes an auxiliary verb that works as a symbol of formality. In those cases, ですcan not be replaced by だ. 

Let’s see some examples:

雨です→ 雨めだ → Correct 

It’s raining.

美味しいです → 美味しいだ→Incorrect 

It’s delicious.

When using verbs + です, it’s important to remember the different types of conjugations, because some conjugations do work withです and others do not.

Examples:

*食べる → Eat

*よむ→ Read

食べるです→Incorrect 

食べない です→ Correct 

読んだです→Incorrect 

読まなかったです→ Correct 

Even though the different uses of です could be a little bit confusing, don’t be discouraged. Actually, it’s not as hard as you might think. If you pay attention to the differences and practice —  before you know it, you’ll be using です without even thinking. 

Always remember, practice, make mistakes, and enjoy the journey! 

Until next time!

About the author: Génesis A. Villar is a language enthusiast, passionate about new cultures, psychology, art, and everything that involves the process of learning. She speaks Spanish, English, and Japanese. Currently, she is learning German, while trying to navigate life in a city on the west side of Germany.