Learn Hardcore Japanese: tosyokan ha kirei desu.

In English we usually just say The library is clean, but in Japanese the topic marker は tells you what the sentence is talking about overall, not necessarily the grammatical subject in the strict English sense.

Why is there no separate word for “is” in the sentence?

Japanese does not use a separate verb like English to be here. Instead, です works as the copula (a linking verb like is / am / are) and also adds politeness.

きれい = clean / pretty
きれいです = is clean / is pretty (polite)

So 図書館はきれいです already includes the idea of “is” inside です. You do not need an extra verb.

What exactly is です and how polite is it?

です is the polite copula, roughly corresponding to is / am / are in English, but it mainly marks polite style, not tense.

It makes the sentence polite and neutral/formal enough for most everyday situations.
It does not by itself indicate past tense.
- Present / general: 図書館はきれいです = the library is (generally) clean.
- Past: 図書館はきれいでした = the library was clean.

Using です is appropriate with strangers, teachers, co‑workers, etc. With close friends, people often drop it or use だ instead.

Why does きれい, which is a な‑adjective, appear without な here?

きれい is a な‑adjective, meaning:

Before a noun it usually takes な:
- きれいな図書館 = a clean / pretty library
Before です / だ (used predicatively, as the sentence’s “is …” part), it appears without な:
- 図書館はきれいです = The library is clean / pretty.

So the pattern is:

[な‑adjective] + な + noun → きれいな図書館
noun + は + [な‑adjective] + です → 図書館はきれいです

No な is used before です.

Does きれい mean “clean” or “pretty”?

きれい can mean several related things, depending on context:

For places / rooms / things:
- clean, neat, tidy, well‑kept
- この部屋はきれいです = This room is clean / tidy.
For people / faces / scenery, etc.:
- pretty, beautiful, good‑looking
- 彼女はきれいです = She is pretty / beautiful.

In 図書館はきれいです, for a library, learners usually understand it as:

The library is clean / neat / nice.

It can also carry a sense of nice and pleasant‑looking, not just hygienically clean.

Why is there no article like “a” or “the” before 図書館?

Japanese does not have articles like a / an / the. Context decides whether you understand 図書館 as:

a library
the library
libraries in general

For example:

Talking about your school: 図書館はきれいです will usually be taken as
- The library (here / that we both know) is clean.

So when translating, you choose a or the based on what makes sense in the situation, even though Japanese just says 図書館.

Why is there no pronoun like “it” in the Japanese sentence?

Japanese often omits pronouns when they are clear from context.

In 図書館はきれいです:

The topic 図書館 already tells you what the sentence is about.
The idea “it” in English (as in It is clean) is simply understood and does not need to be said.

A more literal feeling is:

As for the library, (it) is clean.

The subject or pronoun is rarely repeated when it is obvious from the conversation.

What is the difference between 図書館はきれいです and 図書館がきれいです?

Both can be translated as “The library is clean / pretty”, but the nuance differs:

図書館はきれいです
- は marks topic: As for the library, it is clean.
- Neutral description, often giving general information.
- Could also be used in contrast:
  - 図書館はきれいですけど、トイレはきたないです。
    - The library is clean, but the toilets are dirty.
図書館がきれいです
- が marks subject / focus: it often answers “which one is clean?”
- Nuance: The one that’s clean is the library.
- Emphasizes that the library (and not something else) is the thing that’s clean.

So:

General statement about the library → 図書館はきれいです
Emphasizing which place is clean → 図書館がきれいです

How would I say this more casually, without politeness?

In casual speech (to close friends, family, etc.), you can drop です or use だ:

図書館はきれいだ。
- Still feels like a statement, but casual / plain.
In very casual conversation, people may even just say:
- 図書館、きれい。
  - Topic is implied; sounds like: The library’s nice / clean.

So levels:

Polite: 図書館はきれいです。
Plain: 図書館はきれいだ。
Very casual / spoken: 図書館、きれい。

Can I change the word order, like きれいです図書館は?

Japanese word order is more flexible than English, but the basic and most natural order for this type of sentence is:

[topic] は [adjective] です
図書館はきれいです。

Other orders like きれいです、図書館は can appear in speech for emphasis or afterthought, but they sound like:

It’s clean… the library, I mean.

This is not the normal way to introduce the information. For a beginner, it is best to stick to:

図書館はきれいです。

How do you read 図書館, and what do the kanji mean?

図書館 is read:

としょかん (toshokan)

Kanji breakdown:

図 – diagram, plan, drawing
書 – writing, book
館 – building, hall

Put together, 図書館 is literally like “book-building”, i.e., a library.