There are many great Japanese-inspired sims in Second Life. I most recently reviewed Miyagawacho Hanamachi, (Shrine River Flower Town) and Taka No Sakura here earlier this year. These builds are situated on virtualizations of the mountainous coast and spine of Japan, and remind me of the area around Kyoto Japan -- which I have visited and was charmed by in real life. Blue Lotus Okiya, which dates back to 2007 is a roleplay and retail sim, one that looks very authentic. I found the layout of the islands against the water, and the charm of all the buildings to make this a must-see Second Life Destination. Highly recommended for a visit.
All photography was taken with Windlight Setting (TOR) Sunrise Coastal 3, which I like for its warm pink and orange hues.
See a great review and excellent photography over at the Slice of Life Blog: