Be a gentleman
What to do to please your Japanese girlfriend?
When I first started dating my girlfriend (now my wife) in Japan back in 2007, something struck me real hard.
Every time I was acting like a gentleman by doing things like opening doors, walking on the "street side" of the sidewalks, letting her order first, she looked surprised, borderline uncomfortable.
I didn't take time for me to understand why she was that surprised: most Japanese men don't do such things - they are very macho.
Even if the notions of chivalry and honor or Bushido, the way of the Samurai, is very much alive in every aspect of the Japanese society, it's not really the case in the couple.
So if you want to seduce your Japanese girlfriend, BE A GENTLEMEN, you will win her heart.
A true gentleman is polite to everyone, in action and words and is always in control of himself, body and mind. Just observe simple manners, at all time, open doors, pull out chairs, let her order first, let her walk on the "inner" side of the sidewalk, she will be amazed. When dating, always offer to pay for drinks, even if you know she’ll refuse. Chances are, she never experienced that in her life.
Demonstrate the proper social manners by allowing her to finalized her thoughts and phrases without Interrupting her. The contrary demonstrates a tremendous lack of social skills.
She might be uncomfortable the first few times you let the gentleman in you shine, but trust me, this will make her heart melt just for you.