koma wo ugokasu.

It is read こま を うごかす.

• 駒 = こま
• を = pronounced o
• 動かす = うごかす

So the whole sentence is こまをうごかす.

Here, 駒 means a game piece, especially a piece used in a board game such as shogi or sometimes chess-like pieces in a general sense.

A learner may already know 駒 from shogi, where it very commonly means a shogi piece. In this sentence, it means the thing being moved on the board.

を marks the direct object of the verb.

In this sentence:

• 駒 = the thing being moved
• 動かす = to move something

So 駒を動かす means to move a piece, where 駒 is the object receiving the action.

This is a very common question because 動く and 動かす are related but different.

• 動く = something moves / something is moving
  → intransitive
• 動かす = to move something
  → transitive

So:

• 駒が動く = the piece moves
• 駒を動かす = someone moves the piece

Since this sentence has を and an object, the verb needs to be the transitive one: 動かす.

動かす is in the dictionary form (also called the plain form).

This form can be used for:

• general statements
• instructions in certain contexts
• casual speech
• listing actions as a basic form of the verb

Depending on context, 駒を動かす could mean things like:

• move a piece
• to move a piece
• I move a piece
• you move a piece

Japanese often leaves that extra information to context.

Yes, possibly — but this is completely normal in Japanese.

Japanese often omits the subject when it is obvious from context. So 駒を動かす does not explicitly say who moves the piece.

Depending on the situation, it could imply:

• I move a piece
• You move a piece
• One moves a piece
• To move a piece

The subject is understood from the surrounding context, not from the sentence alone.

In normal Japanese writing, there are usually no spaces:

• normal writing: 駒を動かす。

Spaces are often added in teaching materials to make the parts easier for learners to see:

• 駒 / を / 動かす

So the spaces are just for learning convenience, not standard writing.

The particle を is historically connected to the sound wo, but in modern standard Japanese it is normally pronounced simply o.

So in this sentence:

• written: を
• pronounced: o

This is something all learners have to get used to, and it is totally normal.

Yes, depending on context, it could function like a simple instruction or action label, especially in a game explanation, rule book, or textbook.

However, by itself, 駒を動かす is just the plain dictionary form. More direct instruction forms might be:

• 駒を動かしてください。 = Please move the piece.
• 駒を動かせ。 = Move the piece. (strong/commanding)
• 駒を動かします。 = I/you move the piece. / will move the piece. (polite, depending on context)

So the sentence as written is neutral and basic.

Not only for shogi, but shogi is one of the most common contexts.

駒 can mean a small piece used in certain games or devices, but in modern Japanese learners most often encounter it as:

• a shogi piece
• sometimes a board-game piece more generally

The exact image depends on context, but if you see 駒を動かす, a board game or strategy game is a very natural interpretation.

Yes. The plain form 駒を動かす is not especially polite. A more polite version would be:

• 駒を動かします。

If you want to ask someone politely to do it:

• 駒を動かしてください。

So the sentence in your example is the basic plain form, which is the form learners usually study first for vocabulary and grammar patterns.