A chair, "western" or Chinese, can involve some pretty tricky joinery. Note the use of what I'll call "leg abutments" to deal with racking. And notice the unusual mitered joint in the lower left of the image below. Also note the joint at the front of the arm rest. To discourage lifting this chair by the arm rests, a decorative element is added below it, both the add some strength - but maybe also discourage lifting the chair by its arm rests.
LIke their later European counterparts, Chinese furniture makers found "frame and panel" components were pretty strong - and could be combined to make all sorts of things. Over time, the panel atrophised and either became a decorative element or was eliminated entirely.