基本助詞 · Core case markers
を
Object marker
Indicates the noun that undergoes the action of a transitive verb. Also marks movement through a space with verbs of motion.
When to use
- Only used with verbs that take a direct object
- Movement verbs: 道を歩く (walk along a road)
- を is pronounced o in modern Tokyo Japanese
How to use
- 1Place を after the noun phrase that is the object.
- 2The verb must be transitive (or a motion verb with a path).
- 3Objects without を are possible in casual speech when context is clear.
Nuance & non-standard uses
Patterns that go beyond the textbook default — contrast, omission, register shifts, and mixed particles.
Dropped を in casual speech
Objects are routinely unmarked when the verb strongly implies them (食べる, 見る, 書く). Adding を is correct but can sound textbook-stiff in fast conversation.
もうご飯食べた？
Did you eat (meal) yet? — を omitted.
映画見に行こう。
Let's go see a movie.
を with motion verbs (path / traversal)
歩く, 渡る, 飛ぶ, 泳ぐ, and similar verbs mark the space traversed with を, not に. This is a non-English mapping — the path is treated like a direct object of motion.
橋を渡る。
Cross a bridge — the bridge is the traversed span.
空を飛ぶ。
Fly through the sky.
する-compounds: を vs zero object
Many する-compounds allow both 勉強する and 勉強をする. The version without を is often more colloquial; を can add a deliberate, slightly formal or emphatic feel. Some compounds strongly prefer one form (相談する vs 相談をする both exist with nuance).
もう一段勉強した。
Studied a bit more — no を.
一度相談をしてみよう。
Try consulting once — を emphasizes the act as a discrete event.
を marking the "undergoer" in passive / adversity
In passive and adversity constructions (私は先生に褒められた / 雨に降られた), the logical object of the verb can appear as を on the affected party in some patterns, while the agent takes に. This is N3+ territory but explains non-textbook を.
弟は虫に刺された。
My younger brother was stung by a bug — affected party は, agent に.
Examples
本を読む。
Read a book.
公園を散歩する。
Take a walk through the park.