Japananese dual nationals legally allowed 2 wives

I heard of one first generation born Japanese male that he also being a canadian could have one Japanese wife back home, and one Caucasian wife in Canada. He said that so long as he doesnt register his Caucasian wife in Japan, and the marriage is conducted in Canada, and not in Japan, he can still have a Japanesewi
wife. He can then fulfill his obligations as a first born son at the same time, being happy with a nice beautiful blond Canadian. The children, of course, will only be registered as a Canadian, and not Japanese. How about that eh? Japan will do nothing to him for this act!