I have been married to three Japanese women.
My advice is to get some dating experience with them before marrying, but that is the same with any women not just Japanese. Also, if at all possible, live with any woman before marrying. One problem with marrying women from "certain countries" is that there is a group of them who are hot to marry a foreign man and many, but not all, turn out to be absolute nightmares as wives. And frankly, I believe that men hot to marry foreign women are more likely be nightmares as well.
None of my wives have been such women. My previous two marriages fell apart for very different reasons.