My family lawyer mentioned as below :
If you want we can go ahead without an immigration lawyer and you can fly to Canada with the kids and take your chances with Canadian Border Services and hope that all goes well. However I think you should be very reluctant to do this. It may be that everything will be fine. However it may be that problems will arise due to the fact that you have stayed out of the country too long. It may be that you might be detained and returned to Japan, with the kids handed over to XXX. Or you might be allowed into Canada after a scary period of detention and questioning, but only as a visitor and only for a short period of time, with the kids being handed over to XXX during your period of detention. I do not know what will or might happen and neither do you and I think that should worry you. However it is up to you to decide. If you tell me that you want to go ahead without getting advice from an immigration lawyer and having an immigration lawyer on call when you arrive in Canada, then that is your choice to make.
Is this be possible to happen? I just feel a pressure to hire an immigration lawyer from my family lawyer.
I'm planing to do without an immigration lawyer and I will prepare the e-mail correspondence to proof my ex made me to not come back to Canada for a long time. Isn't this enough?