なり・
Two forms, told apart by the verb in front. After a dictionary form, "the moment they did it": one person does something and at once does something abrupt. After a た-form, "and stayed that way".
the moment
As soon as he entered the room, he opened the window.
and stayed that way
He went into the room and did not come out until morning.
The moment
Verb in the dictionary form + なり
帰る → 帰るなり, though the story is in the past.
And stayed that way
Verb in the た-form + なり（で）
座った → 座ったなり. The で is optional.
The moment: 帰るなり
Both halves are about one person, usually someone you were watching. They do one thing and, the very next instant, something abrupt: shout, burst into tears, walk out. It tells what happened: never a request or a plan.
Novels tell stories this way, and so do people, out loud.
The moment she read the letter, her expression changed.
The moment the child had his shoes off, he dashed upstairs.
Dad went straight to sleep the moment he got in yesterday.
As you would say it at home.
Not said: 私が
(The moment I sat down, the phone rang.)
Two subjects, me and the phone: 席に着いたとたん、電話が鳴った.
なり or や否や?
As soon as the company president took his seat, he pointed out a flaw in the documents.
The point is how abrupt he was: no greeting first, straight to the fault. People say this one aloud too.
No sooner had the company president taken his seat than he pointed out a flaw in the documents.
Written. The point is the timing: seated, and at once.
And stayed that way: 座ったなり
Someone sits down, goes in, falls silent or leaves, and that is how things stay. It is old-fashioned and bookish, and rare today: you will mostly meet it in older novels. The everyday words are たまま and たきり.
He sat down on the sofa and didn't move until morning.
In everyday words: 座ったまま.
She kept her head lowered and did not speak until the end.
He left home five years ago, and his whereabouts are still unknown.
In everyday words: 家を出たきり.
Close neighbours
が早いかN1
"No sooner … than" in written storytelling. The two halves can be about different people or things. A rarer twin of や否や.
No sooner had the alarm sounded than the passengers ran for the exit all at once.
や・や否やN1
"The moment" in written storytelling and news. The two halves can be about different people or things. や alone is shorter and stiffer.
The moment the train arrived at the station, the waiting passengers all boarded at once.
そばからN1
Usually not one event but every time: something is done, and at once it is undone or outrun. Said in conversation too.
I forget new words as fast as I learn them.
たままN4
A state is left as it is: still sitting, the window still open.
I accidentally fell asleep with the window open.
たきりN3
"And nothing since": someone left, and the return you expected hasn't come.
My father went out this morning and still hasn't come back.
Other なり
なり～なりN1
Twice in a row: this, or that, or something like them.
Please order tea, coffee, or whatever you like.
Check yourself
1Which one fits?
彼は
Choose an answer to see why.
2Which sentence sounds natural?
Choose an answer to see why.
More sentences
The instant the boy saw his mother, he started running.
The moment my father opened the newspaper, he frowned.
As soon as the cat was let out of the carrier, it hid under the shelf.
The man remained standing in the doorway and watched us for a while.
The ship left the harbor and never returned.