kono youki ha kirei desu.

It is read:

この ようき は きれい です。
Kono yōki wa kirei desu.

A few pronunciation notes:

• この = kono
• 容器 = yōki
• は is written ha, but in this sentence it is pronounced wa
• きれい = kirei
• です = desu (though in natural speech, the u is often very light or almost silent)

この means this and must come directly before a noun.

So:

• この 容器 = this container

Unlike English, you do not usually say この by itself before a pause and then add the noun later. It directly modifies the noun that follows.

Compare:

• この容器 = this container
• その容器 = that container
• あの容器 = that container over there

Because この is not a separate noun here; it is a determiner that directly modifies 容器.

So この容器 works as one noun phrase: this container.

This is similar to English:

• this container
• not this of container

In Japanese, demonstratives like この / その / あの go straight before the noun with no particle in between.

は marks the topic of the sentence.

So in:

この容器はきれいです。

the topic is この容器 = this container.

A natural way to think about it is:

• As for this container, it is clean/pretty.

This does not always match English word-for-word, but it helps explain the grammar.

This is a very common beginner question.

The character is written は, but when it is used as the topic particle, it is pronounced wa.

So:

• この容器は = kono yōki wa

This is just a standard feature of modern Japanese spelling. The same kind of thing happens with a few other particles too, such as:

• へ written he, but often pronounced e as a particle
• を written wo, but usually pronounced o

Yes, but specifically it is a na-adjective in Japanese grammar.

That is important because Japanese has two main adjective types:

• i-adjectives like あつい (hot)
• na-adjectives like きれい (clean / pretty)

Even though きれい ends in い, it is not an i-adjective. It behaves like a na-adjective.

That affects how it is used:

• きれいです = is clean / is pretty
• きれいな容器 = a clean / pretty container

Because な is only used when a na-adjective comes directly before a noun.

Here, きれい is not before a noun. It is the predicate of the sentence:

• この容器はきれいです。 = This container is clean/pretty.

But if you put きれい directly before 容器, then you need な:

• きれいな容器 = a clean/pretty container

So:

• きれいです ✅
• きれいなです ❌

です makes the sentence polite and completes the statement in a standard polite style.

So:

• この容器はきれいです。 = polite
• この容器はきれい。 = plain / casual

With na-adjectives, です is very commonly used in polite speech.

It works a bit like saying is in English, but it is better to think of it as a polite sentence ending rather than a direct one-to-one translation of is.

It can mean either, depending on context.

きれい often means:

• beautiful
• pretty
• clean
• neat

With 容器 (container), the most natural meaning is often clean rather than beautiful, because containers are often talked about in terms of cleanliness.

So in this sentence, clean is probably the intended meaning, though context always matters.

Sometimes yes, but the nuance changes.

• この容器はきれいです。 = As for this container, it is clean.
• この容器がきれいです。 = This container is the one that is clean / This container is clean (with more focus or contrast)

Very roughly:

• は introduces the topic
• が gives stronger focus to the subject

For a simple neutral statement in a textbook, は is very common.

The structure is:

この容器 + は + きれい + です

Or:

noun phrase + topic particle + na-adjective + polite ending

In English order, it comes out as:

• This container is clean.

Japanese often places the descriptive part near the end of the sentence.

Yes. In normal Japanese writing, you would usually write it without spaces:

この容器はきれいです。

Spaces are often added only in beginner materials to make reading easier.

Yes, if the container is clear from context.

• この容器はきれいです。 = This container is clean.
• これはきれいです。 = This is clean / pretty.

これは is less specific by itself, while この容器は clearly names the object as a container.

So both are correct, but the original sentence is more explicit.