Why go
The important question is the complete journey, rather than a visa label considered on its own. A route from mainland China to Hong Kong and back raises a return-entry question that a one-way departure does not. Resolve that distinction before committing to onward transport or accommodation.
The full story
Write down each intended entry, the purpose of the visit and the travel document you will use. For a mainland China–Hong Kong–mainland China itinerary, include the return leg explicitly when seeking official advice. Do the same for a Macau excursion or a flight connection involving another border. Ask the Hong Kong Immigration Department about your Hong Kong visit and the relevant Chinese visa authority about the mainland portion. Questions about tourism, employment, study and residence need answers for the actual activity planned; an account of someone else’s holiday cannot settle them. Confirm the application procedure, required supporting documents and timing directly with the authority handling your case. Build the journey around those answers. Avoid assuming that a short stay, an existing document or a purchased ticket settles a separate entry question. This is particularly useful when Hong Kong is an intermediate stop rather than the final destination.