eiga wa yoru ni hajimarimasu.

topic particle

Breakdown of eiga wa yoru ni hajimarimasu.

• 映えい画が: movie
• に: time particle
• 夜よる: night

Questions & Answers about eiga wa yoru ni hajimarimasu.

Why is 映画 followed by は here instead of が?

は is the topic marker, telling us “as for the movie…,” while が would mark the movie as the grammatical subject and present it as new information.

• Using 映画は夜に始まります frames the sentence around the topic “the movie” and then tells us when it starts.
• If you said 映画が夜に始まります, you’d simply state the fact “the movie starts at night,” with no topical nuance or implied contrast.

Why is 夜 followed by the particle に?

に marks 夜 as a specific point in time (“at night”). In Japanese:

• に attaches to precise time words (hours, days, “night,” etc.).
• 夜に means “at night.”
  Without に, the sentence would sound unnatural when referring to that specific time.

Could we omit the に and just say 映画は夜始まります?

No. For words like 夜, に is required to mark the time. Omitting に here makes the sentence ungrammatical.
Note, however, that some time expressions (今夜, 毎日, 明朝) don’t need に, but plain 夜 does.

Why doesn’t 映画 take を as in “direct object”?