Seek tax guidance in Canada and whereever you choose to reside! Canada has tax treaties with Japan ! If you are registered as resident in Japan you are responsible for paying local/pref./national taxes, also include the national health system. You might have to declare non-residency in Canada (which takes time) and more or less not be able to have bank accounts, credit cards, property, stock/bond, access to health care etc in Canada as you will no longer be resident there. If you decide to stay resident in Canada you will have to be in Canada 181 days of the year and pay taxes etc there. Tres PITA !