Worth Having Kids Keep Up Their Japanese?

I lived in Japan for about seven years and my wife is Japanese. Our kids speak English and Japanese well while living in the USA.

We kept up their language skills in English and Japanese by having one of us only speaking one language to them - me: English, my wife: Japanese.

One thing I want to do more to improve their language skills and their connection to their Japanese heritage is have them spend time in Japan while they are on vacation.

Almost have a “dual life” - most of the year they’re speaking English. Any vacation time is in Japan where they living another world.

After a recent visit - I realize that for my kids to maintain their Japanese language skills so they can study in Japan. For this level, they can’t just visit during vacations, because every one of their peers are studying Japanese the whole year.

Japanese schooling is a homework driven study style and in a way, I don’t want my children’s childhood to be so full of homework that they don’t have time to relax and be a child.

With this new information - I am reconsidering how my family & I maintain a healthy connection to our heritages.