Japanese learners often understand the particle を as a direct object marker, but later, in their study, they find it used in a strange context, which cannot be explained with that use. In this post, I decided (briefly) to list those and explain them in a few words.
But first, a short historic note. The hiragana を probably comes from kanji 遠 written in the cursive sōsho style. The original spelling was ‘wo’, which eventually changed to ‘o’, however, historic spelling has been preserved just like in the case of the particle ‘は’ and particle ‘へ’.
Well, let’s move the usages:
1) expresses direct object with transitive verbs:
Do you eat curry every day?
We learn Japanese every day.
I watched the news yesterday.
Because only one particle を can be used in the clause (part of the sentence), with causative form (to make someone do something) the second を indicating a person that is made to do something is replaced with に.
Feed the tablet to the dog. (Make the dog eat the tablet.)
2) With intransitive verbs expressing movement (歩く 飛ぶ 登る 泳ぐ) it expresses what we are moving along, over, or through.
Swimming across the north pole is not something ordinary.
To be walking across wide, open space.
In order to climb steep hills, you have to go slowly at first.
(By the way, when particle に is used with 登る there is a nuance difference, for example:
it indicates going up, to the peak, while using を indicates just going up the mountain, not necessarily aiming for the top)
3) Marking place where some movement stars, ‘away’, ‘from’, ‘off’.
I am going away from Amsterdam. (I am leaving Amsterdam.)
To leave one’s seat.
Have you just left the train?
I left the Netherlands.
4) を can also mark a cause with verbs expressing emotion like 悲（かな）しむ、喜（よろこ）ぶ and 怒（おこ）る。
Mary was very sad about not going back to US for the holidays.
He was pleased with that gift.
Is he mad because of me?
5) You might also encounter it in construction conditional ば（たら・と）ものを, where it means ‘but/although’. The を in it expresses exclamation/concession, functions of を from classical Japanese.
“If I had quit smoking much earlier I would have ended up without any health problems, **but** now it is too late.”
Tony: “Dear God, Boris, it would have been good if you had just shut up and died, **but…**”
By the way, there are cases where particles が and を are both accepted.
For example with auxiliary たい (to want):
I want to eat a hamburger.
According to some, が indicates the stronger feeling of ‘wanting’.
With potential form:
Redditor can read Japanese.
With 好き (many people are surprised that it is allowed):
Holo, I can see why Lawrence loves you.
Well and that’s all folks 🙂 I believe that をwon’t surprise you anymore.
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I am mrnoone, and this was briefjapanese.