>>505
It’s grammatically correct, but it sounds unnatural in real conversation.
We usually say “Mika is back” or “Japan is back”, not “has been back”.
Because “be back” already means “has returned and is here now.”
Using “has been back” sounds like you’re adding “has” twice — it feels redundant.
Native speakers use “has been back” only when they say how long:
👉 “Mika has been back for a week.”