I am confused with the usage of 午前中 and あさ. When should they be used properly?

明日のあさに銀行で口座を開きます。

明日の午前中に銀行で口座を開きます。
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2014-05-16T15:09:33.800
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2014-05-16T18:54:04.403
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question
word-choice
When do I have to use 午{ご}前{せん}中{ちゅう} and 朝{あさ}?
They mean more or less the same thing. In terms of more subtle nuances, note
that 朝【あさ】 is the native Japanese word, while 午前中【ごぜんちゅう】 is derived from
Chinese. The Japanese language has many of these native / Sinic pairs that
mean mostly the same thing, a bit like how English has many pairs of terms
that mean mostly the same thing, where one term in the pair originally came
from Anglo-Saxon or other Germanic roots, while the other term in the pair
originally came from Latin or Greek roots. Just as in English, where the term
that was originally from Latin or Greek often comes across as slightly
"fancier" or more formal, it's usually the same in Japanese, where the Sinic
term is often considered to be a higher
[register](https://en.wikipedia.org/wiki/Register_\(sociolinguistics\)).

So whether to say 朝に or 午前中に in your sample sentence is really a matter of
social context and stylistic word choice.
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2014-05-16T15:39:23.483
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If you mean "morning", I think they're often interchangeable. The native
Japanese 朝 is more common, and if I search the [_Balanced Corpus of
Contemporary Written Japanese (BCCWJ)_](http://www.kotonoha.gr.jp/shonagon/)
for your particular phrase, we find about a five-to-one ratio in favor of 朝:

```

       明日の朝に　　　　　50 results
       明日の午前中に　　　10 results
    
```

In general, I would say there's no difference in meaning. Both typically refer
to "morning", which is most commonly the period of time after the sun rises.
When I look up 朝 in dictionaries, they're ambiguous about when it ends--for
example, 明鏡国語辞典 says it can refer to either a short while after the sun rises,
or it can extend all the way to roughly noon:

> 夜が明けてからしばらくの間。また、夜が明けてから正午ごろまでの間。

Literally speaking, you might expect 午前中 to refer more properly to the twelve
hours from midnight to noon, so that would be a difference in meaning. And in
certain contexts such as [weather
forecasts](http://www.jma.go.jp/jma/kishou/know/yougo_hp/saibun.html), it has
exactly that meaning, while 朝 is more restricted, so they aren't always strict
synonyms. But in many contexts, I think 午前中 refers to roughly the same span of
time as 朝.

Sometimes 朝 might be conceptualized more like a point in time, while 午前中 is
always a span of time thanks to 中. So 朝ずっと is a little unusual, but 朝からずっと
"ever since this morning" is fine; and 午前中ずっと "all morning" is fine, while
午前中からずっと is silly:

```

       朝ずっと　　　　　　1 result
       午前中ずっと　　　　11 results
       朝からずっと　　　　28 results
       午前中からずっと　　0 results
    
```

I think Eiríkr Útlendi is correct that the Sino-Japanese 午前中 belongs to a
slightly more formal register, but it's a common phrase and I think you can
use it in casual conversation if you like.
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2014-05-16T16:44:06.000
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answer