Solid Koa wood back and sides - beautiful, I hear it is on the endangered wood list now. Koa is from Hawaii and really seems to come alive when you tune down a little bit. No wonder the Hawaiian players discovered the "Slack Key" method of guitar playing! Hard to see but you might notice the center line of the back matches the Rossette design around the soundhole. Classy. Dig that Koa wood grain, sometimes I look at it and weep. I tend to do that with J-lo's backside as well.