The object particle を lets us move from being able to say, “Robert ate” to “Robert ate an apple”. In fact, defining the object of the action for transitive verbs is actually only one of its uses. It can be used to define:
The direct object of an action
The point of departure
The point of passing or the route of an action
I will give examples of all three usages, but the order above also reflects the frequency of use—most times you hear or see the object particle it will be used to define the direct object of an action.
While を is romanized and typed on a keyboard as “wo”, it is pronounced almost identically to “o” (お) in modern spoken Japanese.
1. The Direct Object of an Action
We’ve seen the sentence structure below when we looked at verb conjugations—the topic of the sentence coupled with a verb.
私は 食べます。
I will eat.
The particle を is used to define the object of the transitive verb—the “what are you eating?” in this case.
私は 野菜を食べます。
I will eat vegetables.
先生は 数学を教えました。
The teacher taught mathematics.
山田さんは 水を飲みました。
Yamada-san drank water.
さん is often translated as Mr. or Mrs. in English. While this is the closest direct translation, it is arguably a mistake. Orally addressing someone as Mr. or Mrs. in English is formal and this results in an understandable desire for learners of Japanese to drop the さん altogether in an attempt to be more friendly. In fact, さん does not imply such a sense of distance—you will hear it being used to address colleagues and even amongst friends. Don’t think of it as Mr. or Mrs.—think of it as さん.
学生は 面白い本を読みませんでした。
The student didn’t read the interesting book.
2. The Point of Departure
を can also be used to denote the point of departure.
電車を降ります。
To get off the train.
家を出ます。
To leave the house.
3. The Point of Passing or Route of an Action
This usage is introduced here for completeness but will be used much later.
信号を 曲ります。
To turn at the traffic lights.
公園を通ります。
To go through the park.
The Position of Counters
Counters go after the relevant particle for the object that is being counted and before the verb. Many learners of the language trip up here because we instinctively want to put the counter directly next to the object it’s counting. For example, in the sentence, “I will read two books”:
私は 本二冊を読みます。(✘)
私は 二冊本を読みます。(✘)
私は 本を二冊読みます。(✔)
The Object Particle with する
The verb する (“to do”) was introduced earlier. Belonging to group 3, its irregular conjugation patterns might not have earned it much popularity, but here’s the reason that it’s about to become your favourite Japanese verb: it can be added to a huge number of nouns to create a verb. Essentially, it enables us to say things like “to do study”, “to do graduation”, and “to do cooking”. This means that once you know the noun you can easily form the verb.
勉強を します
To study.
電話を します。
To make a phone call.
料理を します。
To cook.
We can actually drop the object particle altogether.
勉強します。
To study.
However, when we want to define what we are studying then we cannot use the first structure since we would have two direct objects for the same verb. For example, “to study mathematics”:
数学を勉強を します。(✘)
数学を勉強します。(✔)
If we want to use the object particle after the noun “study” then we need to use the possessive particle so that the verb “to do” can act on the noun “the study of mathematics”.
数学の勉強を します。(✔)
To study mathematics [to do the study of mathematics].