If you want a cheap flight from Hong Kong to Tokyo, you've got 11 airlines to choose from.
Make sure you use the search options above to search for flights to other airports in Tokyo, not just New Tokyo International Airport. The more options you look at, the better your chance of finding a cheap deal. Just so you know, the flight typically takes 6 hrs 35 mins.
There are about 41 flights to or via Tokyo every week, so you have plenty of options.
If you're planning on going to Tokyo during this time, you could take a look at other airport options. Or you could try to get a last-minute bargain.