The relevant document is here: http://www.moj.go.jp/content/001226222.pdf Question 2 asks you to explain the history of your relationship in detail.
I'd like to know if anyone had or has heard of problems related to the way this is answered. Is there anything specific that needs to be included?
I'm asking because it's my spouse (Japanese national) who has to fill out this questionnaire, but we disagree about how to answer Question 2. She is writing a novel about how we met, but I think it's more important to demonstrate that we don't have a sham marriage–i.e., it doesn't have to be that long, but include a few details about living together and participating in her extended family events. I'm concerned she's going to do too much without doing enough.