Godline, SweetTokyo and Neffiline gave you great tips and I do agree with most of them.
One thing that you also should keep in mind that the Yen is super strong now... and no matter what the government tries, the Holidays won't change that.
In my opinion, you should definitely wait till the end of January and see how things change. You won't get a cheaper flight - 1300CAD sounds great by the way - but have a good chance to get more yen for your dollars.
Decided already on how and where you'll travel within the country?
Good Luck,
Japean