Japanese surname for a character in my book?

So, I'm trying to find a suitable surname for my character Emi. She is of Japanese descent and I want her to have a last name that showcases that but is still easily pronounceable. Emi is a very fun character, she does not hate, she loves--basically everything. She's very sweet, very fun-loving. She loves to sing, even though she can't do it well. Her voice (both singing and speaking) is very high, and childlike. She never swears, never speaks badly of someone. She hates arguments almost as much as she hates being the mediator. She's overweight, but not exceedingly so. She has subtle baby fat, but it really, really suits her. She has a round face, and dark eyes, and long hair. She's beautiful and unique. She's my MC's best friend, and they live together. (But, they're not together. They will not end up together, either. My MC has his eye out for someone else. And, Emi doesn't need a guy to complete her.) Anyway, thanks in advance.