Learn how to speak Japanese. Even if she is fluent in English(or which ever language he speaks), it would be great to know her language too.
Learn Japanese history. This step is not so much as to impress her, as it is to impress her family.
Take her to Japanese restaurants.
Learn Japanese recipes. And of course, we all know that sushi is a very famous Japanese fish recipe.
If the relationship becomes steady, and you and your girlfriend decide to marry, have the wedding in a Shinto ceremony.
How old is your Japanese girlfriend? You see, if she just turned 20 years old this year, there is a Japanese holiday, which falls upon the second Monday of January, which is held in honour of all the people who turned 20 years, during the previous year. It is called ‘Coming of Age’ Day. So, if she is still just turning 20 this year, go ahead and celebrate her birthday, but in addition, have a little surprise party for her on the second Monday in January too.
Some families won’t like their children dating or marrying outside of their culture.
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The science of love
How to Date a Black Girl
How to Choose a Wife