を (o) Particle

The を (o) particle is one of the fundamental grammatical particles in Japanese. While its primary role is to mark the direct object of a verb, it has additional uses, including marking the place of departure or pathway in motion verbs, appearing in fixed expressions, and even being omitted in casual speech.

Mastering the を particle is crucial for constructing natural and grammatically correct sentences in Japanese. This guide will cover all its major functions, along with examples and explanations to help you fully understand its usage.

Direct Object Marker

In Japanese, を is the direct object marker, meaning it connects the object of a verb to the action being performed. This answers the questions “What?” or “Whom?” in relation to the verb.

Structure:

[Subject] は [Object] を [Verb]

Examples:

本を読む。 
(Hon o yomu.)
I read a book.

映画を見ます。 
(Eiga o mimasu.)
I watch a movie.

音楽を聞く。 
(Ongaku o kiku.)
I listen to music.

寿司を食べる。 
(Sushi o taberu.)
I eat sushi.

手紙を書く。 
(Tegami o kaku.)
I write a letter.

In each sentence, を links the object (e.g., 本, 映画, 音楽) to the action (読む, 見る, 聞く). This is the most basic and essential function of を.

を with Motion Verbs (Indicating Pathway or Departure)

Unlike the を + direct object usage, を can also indicate the place of movement when used with motion verbs such as:

🔹 通る (tooru) – to pass through
🔹 渡る (wataru) – to cross
🔹 出る (deru) – to exit
🔹 降りる (oriru) – to get off
🔹 歩く (aruku) – to walk along
🔹 走る (hashiru) – to run along

Structure:

[Place] を [Motion Verb]

Example:

駅を出る。
(Eki o deru.)
→ "To exit the station."

橋を渡る。
(Hashi o wataru.)
→ "To cross the bridge."

公園を散歩する。
(Kouen o sanpo suru.)
→ "To take a walk in the park."

Note:

を vs. で (Place Marker)

  • を emphasizes movement through or out of a location.
  • で marks the location where an action takes place (e.g., 学校で勉強する = “I study at school.”).

Example:

公園を散歩する。 
(Kōen o sanpo suru.) 
To take a walk through the park.

公園で遊ぶ。 
(Kōen de asobu.) 
To play in the park.

Fixed Expressions & Idioms

The を particle is found in many common expressions, especially those using する-verbs (verbs formed by combining nouns with する).

Structure:

 [Noun] をする (To do [something])

Common を + する Expressions:

息をする。 
(Iki o suru.)
To breathe.

運転をする。 
(Unten o suru.)
To drive.

宿題をする。 
(Shukudai o suru.)
To do homework.

質問をする。 
(Shitsumon o suru.)
To ask a question.

買い物をする。 
(Kaimono o suru.)
To go shopping.

These expressions are widely used in daily conversation, and を is always required before する.

Some expressions use を in fixed phrases that don’t require する.

息をのむ。 
(Iki o nomu.)
To gasp in surprise.

責任を取る。 
(Sekinin o toru.) 
To take responsibility.

命を落とす。 
(Inochi o otosu.) 
To lose one's life.

を and Omissions in Japanese

In casual spoken Japanese, the を particle is often omitted, especially when the meaning is clear from context. However, this is more common in informal speech and less frequent in written or formal Japanese.

Example:

本を読む。 (Hon o yomu.)
本、読む。 (Hon, yomu.) (More casual)

映画を見た。 (Eiga o mita.)
映画、見た。 (Eiga, mita.) (More casual)

コーヒーを飲む？ (Kōhī o nomu?)
コーヒー飲む？ (Kōhī nomu?) (More natural in speech)

Omitting を sounds natural in informal speech, but it should not be omitted in formal writing or polite conversation.

Verbs with strong contextual clues (like 食べる, 飲む, 見る) often don’t need を in casual speech.