He didn't go to Japan to find her. She found him in England. I read a memoir last year by a guy named Tony Bramwell. He was a Beatle friend and business associate/flunkie. He said Yoko basically stalked Lennon. She must have seen something in Lennon that told her he was ripe for the plucking, because neither Bramwell nor the other three Beatles wanted anything to do with her. They basically saw her as the flake we see (according to Bramwell's book).
My wife is a huge Beatles fan even from childhood, so she probably knew all that, I am not as impressed except by the sheer output of their music in their heyday. She still blames Paul McCartney for Keith Moon’s death.
Yes. The Lives of John Lennon is another account that says the same thing.