
Questions & Answers about tesshuu ga hajimatta.
It is read:
てっしゅう が はじまった
- 撤収 = てっしゅう
- 始まった = はじまった
So the full sentence is てっしゅうがはじまった.
撤収 is a noun, but it is also a verbal noun (a noun that can combine with する to make a verb).
So you can have:
- 撤収 = withdrawal / pullout / breaking camp
- 撤収する = to withdraw / to pull out / to break camp
In this sentence, 撤収 is being treated as the thing that started.
が marks the thing that is doing or experiencing the action/state of the verb.
Here, the verb is 始まった = started / began.
So 撤収が始まった literally means something like:
- The withdrawal started
- Withdrawal began
The event 撤収 is the thing that began, so it takes が.