kono mokume ha utukusii.

It is read:

この もくめ は うつくしい。

• この = kono
• 木目 = mokume
• は = wa (as a particle)
• 美しい = utsukushii

So the full reading is kono mokume wa utsukushii.

Because は is being used as the topic particle.

When は is a particle, it is pronounced wa, even though the usual reading of the character is ha.

So in this sentence:

• 木目は = mokume wa

This is one of the first pronunciation exceptions learners usually meet in Japanese.

Because この must come before a noun, while これ stands by itself.

Here, この is directly modifying 木目:

• この木目 = this wood grain

Compare:

• この木目 = this wood grain / this grain pattern
• これは = this is...

So you cannot say これ木目.

木目 means the grain of wood, or the natural pattern you see in wood.

It is made up of:

• 木 = tree / wood
• 目 = eye; also mark, appearance, or pattern in compounds

So 木目 refers to the visible lines and patterns in wood.

は marks 木目 as the topic of the sentence.

So the structure is roughly:

• この木目 = as for this wood grain...
• は
• 美しい = is beautiful

A natural way to think of it is:

• As for this wood grain, it is beautiful.

In English we usually would not translate は directly, but it helps organize the sentence in Japanese.

美しい by itself is the plain form.

Japanese adjectives of this type can end a sentence on their own in plain style:

• この木目は美しい。

If you want to make it more polite, you can say:

• この木目は美しいです。

Both are correct. The version without です sounds more plain, neutral, or written.

美しい is an い-adjective.

That means it behaves like an adjective that can directly describe a noun or end a sentence:

• before a noun: 美しい木目 = beautiful wood grain
• at the end of a sentence: 木目は美しい = the wood grain is beautiful

Because it is an い-adjective, you do not need だ after it.

So:

• 木目は美しい。 = correct
• 木目は美しいだ。 = incorrect

Japanese often puts the topic first and the descriptive word at the end.

So this sentence is arranged like:

• この木目 = this wood grain
• は = topic marker
• 美しい = beautiful

English often prefers:

• This wood grain is beautiful.

Japanese commonly saves the main statement for the end, so the adjective comes last here.

Yes, but it would change the nuance.

• この木目は美しい。
  = speaking about this wood grain as the topic

• この木目が美しい。
  = puts stronger focus on this wood grain specifically, often implying contrast like this one is the beautiful one

For a simple neutral statement, は is very natural.

Yes, 美しい is natural here. It sounds a bit more elegant or literary than きれい.

• 美しい = beautiful, often a little more elevated or descriptive
• きれい = pretty, clean, beautiful; very common in everyday speech

For wood grain, 美しい fits very well, especially in writing, description, or formal speech.

You could also say:

• この木目はきれいです。

That sounds a little more conversational.

No. Japanese is normally written without spaces.

The normal writing would be:

この木目は美しい。

Spaces are often added only in beginner materials to make the sentence easier to read.

Yes, in natural English that is often how you would understand it.

Japanese この木目 literally looks like this wood grain, but depending on context it can refer to:

• the grain pattern on this piece of wood
• the wood grain of this object
• this particular grain pattern

So the exact English phrasing may vary, even though the Japanese structure stays the same.

Yes, but it may sound slightly more like written or careful descriptive speech because of 美しい and the plain ending.

• この木目は美しい。 = plain, descriptive, somewhat elegant
• この木目は美しいです。 = polite
• この木目、きれいですね。 = more conversational

So the original sentence is perfectly correct, but its tone is a little more refined than casual everyday chat.