The legs and rails of this Tatami style bed is made entirely without hardware. The rails fit into the leg like a puzzle, making it easy to assemble.
This version of the bed uses a platform to support a standard queen size mattress. It could also be made with bed slats the way a traditional Tatami bed is made. It could also use bona fide tatami mats as well.
The base wood in this particular bed is Eastern Black Walnut, and the accent wood Bubinga (a.k.a. African Rosewood). I can easily, however, imagine many combinations of wood species that would work well in this design.