Particles · N5
を: object and route
The familiar direct-object marker also appears with movement through or away from places.
In short
を most often marks the thing directly affected by a transitive verb: 本を読みます. It can also mark a route traversed or a place left, as in 公園を歩きます and 家を出ます.
How it works
The route use does not mean the park is an “object” in the English sense; Japanese particles mark grammatical relationships that do not always match English labels.
Useful contrast
を is written with を but normally pronounced お in modern Japanese.
Examples
本を読みます。
I read a book.
公園を歩きます。
I walk through the park.
Common pitfall
Do not automatically use を after every noun before a verb. Many verbs require が, に, と or another particle instead.