Breakdown of honyaki wa ashita hajimaru.
Questions & Answers about honyaki wa ashita hajimaru.
は marks the topic of the sentence.
So 本焼きは明日始まる is something like:
- As for the main firing, it starts tomorrow
- The main firing starts tomorrow
The important nuance is that は sets up 本焼き as the thing the speaker is talking about. It can also suggest contrast depending on context, but here it most naturally just marks the topic.
