I'm just applying for my summer student visa for Hong Kong, and I'm a little confused on the visa application.

Under the first section (purpose of application for entry) there are two areas-number of journeys for visit only (sing/double/triple/multiple) and number of journeys for transit only (single/double). What exactly does this mean?

I'll be flying right to Hong Kong but I will also be travelling to China for a few days during my stay, and I'll be going back to Japan afterwards (on my way home to Canada from Japan I have to transfer planes in Hong Kong).
So what am I supposed to check off?