an assembly system permitting separate construction and transport of subcomponents for seating furniture items . the disassembled subcomponents allow for more efficient transportation by eliminating the dead space created by transporting irregularly shaped assembled furniture items . the assembly system includes a seat box having a rectangular frame defining an accessible internal cavity covered by an upper support surface . the assembly system also comprises a back rest having a seat box interface surface and at least arm rest interface surface . the back rest also defines an internal cavity accessible through closable opening for internal access to the arm rest interface surfaces . the assembly system also includes mounting an interface surface to the arm rest for securing the arm rest to the arm rest interface surface of the back rest and the rectangular frame of the seat box .