Cruising holiday to China- is this multiple entry - Australian citizens

Hi
We are cruising later this year and will be joining a cruise in Beijing after a 3 day stay there, and will then cruise to Dalian for a few hours and then onto Shanghai for 3 days, which may include an overnight stay at Xian rather than aboard the ship, then onto Japan. Will this count as multiple entries to China or one entry because we remain in the China sea and don't land anywhere "overseas" between the stops?
The cruise line are vague on this (they as US based so no doubt it costs the same for their visa no matter what) and I don't want to pay a agent just because the answer to a simple question seems quite hard to get s straight answer about.