I'll be taking 2 school age kids for a 2 week trip to Japan. Due to work/school commitments the other kids and wife will stay home.

Traveling from Canada to the USA in the past I got questioned a bit by immigration and they advised me next time I should bring a letter from my wife (I think with a photocopy of her picture ID if I recall correctly) confirming that it was OK for me to bring the kids into the country. It seems they are hypersensitive about the possibility of child abduction.

Planning ahead for Japan, will there be any similar concerns?