It looks like an anime cuirass (i.e a cuirass made from many horizontally rivited lames). It was easier in ye olde days, to control the thickness of smaller pieces of metal. I assume the studded bits would be like a coat of plates with metal plates underneath and the rivits poking out. So he probably wouldn't be able to move his left arm. Also, the cuirass doesn't seem to be attached on the right side. They were close with straps or hinges.

*closed with straps etc