Japanese often does not need a separate word for is in sentences with い-adjectives.
Here, 白い already works as a predicate, so:
You do not need だ or です after 白い in plain form.
So this is natural:
And this is also natural but more polite:
白い is an い-adjective.
In Japanese, い-adjectives can act directly like the main predicate of a sentence.
So:
That is why 白い can finish the sentence by itself.
Other examples:
It can mean either bone or bones, depending on context.
Japanese nouns usually do not show singular vs. plural as clearly as English does. So 骨 can mean:
Context tells you which meaning is intended.
In a general statement like 骨は白い, English often translates it naturally as Bones are white or Bone is white, depending on the situation.
Japanese sentence order is different from English.
A very common pattern is:
topic + は + comment
Here:
So the structure is basically:
As for bones, white.
That sounds incomplete in English, but in Japanese it is a normal sentence.
Yes, it could.
Because Japanese often leaves number and articles unstated, 骨は白い could mean different things depending on context, such as:
If someone is holding one bone and describing it, the meaning might be The bone is white.
If someone is making a general statement, it might mean Bones are white.
Yes, but the nuance changes.
骨は白い = As for bones/the bone, it is white
骨が白い = The bone is white / It’s the bone that is white
For a beginner, the safest idea is:
In this simple sentence, は is very natural for a general descriptive statement.
You can say:
骨は白いです。
This is the polite version.
Compare:
Both are correct. The original sentence is plain and simple.
The negative of 白い is 白くない.
So:
Polite:
All of these are possible, though beginners often learn 白くない first.
In polite Japanese, you can say:
骨は白いですか。 = Is the bone white? / Are bones white?
In casual speech, people often just use rising intonation:
骨は白い？
Japanese does not always need a special word order for questions like English does. Often you just add か or use question intonation.