Jay Chou's song "Peninsula Tin Box", what is the Peninsula Tin Box?

At first, Jay went to a shop and asked, Miss, did you buy a peninsula tin box? I also sang: Think back to the book I just bought, a book called Peninsula Tin Box. So in the song, the peninsula tin box is a book. There is also this book in reality. It is a book by Vincent Fang, but it is actually a photo collection of Jay Chou. But in this song mv, there is really an iron box, and there is a lyric: I can't find the key to the iron box. Perhaps this tin box is used to imply that I can't open (lose) my previous love, so there is another one: the order of the tin box becomes a diary and the air becomes a memory.