That's a beautiful bench and black walnut makes it a "premium" bench. I haven't seen one with the rock-looking end pieces which give it a unique look as it sits there in the garden.
I haven't yet made a bench but I think this is gonna be the year. Perhaps I'll be lucky and a big ole walnut tree will be blown down soon around my parts. If not, then it looks like pine again.
Great work and thank's for posting!