Those rails on walls of a tatami room can serve as a sort of french cleat. So I designed a hook that you can just plop on there. I made a split-in-half version where you won't need supports but will have to glue the pair using superglue. Holes are provided so you can insert alignment pins. Use 5mm length of 1.75 filament as pins. Whole unsplit version also inlcuded and needs support on the "hook" end.