ANA: $600CAD Vancouver-Hong Kong, via Tokyo. Wide availability in 2015.
I found an excellent fare between Vancouver YVR and Hong Kong HKG, via Tokyo HND. There is significant availability through 2015, including long stays and immediate, 0-night turnarounds. You can use ITA Matrix, Google Flights, or Kayak.com to find availability. The fare is a little buggy, but it does show on ANA or for cheaper on some travel agents, where Google Flights or Kayak will redirect you. Here is an example on Kayak.
Is this fare allow a stopover at Tokyo(NRT) or to paid some reasonable extra money to do so. [looking for early feb for 10-12 day, with 4 nights at japan]
The fare rules allow the following for a stopover:
As Japan is Area 3, you can presumably do a stopover in Tokyo for $100CAD more.