A coupling piece arrangement for joining two containers, that are stacked one on top of the other, the coupling arrangement comprising:
- a lower container corner fitting having a normally horizontal upper surface, corresponding to a normally horizontal upper surface of the lower container of the two containers, said corner fitting having a chamfered opening leading to a normally vertical elongate hole with a catch receiving surface leading to a laterally expanded lower hole portion;
- and
- a coupling piece with a stop plate and an upper container coupling projection on an upper side of said stop plate for placement in a corner fitting of an upper container and a lower coupling projection on a lower side of said stop plate for placement in said lower container corner fitting, said lower coupling projection comprising a non-positive locking means including a locking catch extending laterally with respect to a longitudinal direction of the containers and having a friction engagement surface for engaging said catch receiving surface inside said lower container corner fitting, said non-positive locking means for guiding said coupling piece during insertion into said lower container corner fitting with a guided lateral movement of said lower coupling projection away from said catch receiving surface, with a subsequent guided downward movement of said lower coupling projection into said laterally expanded lower hole portion and with a following subsequent guided lateral movement of said lower coupling projection toward said catch receiving surface to bring said friction engagement surface into contact with said catch receiving surface to provide frictional locking of said coupling piece in said lower container corner fitting against torsional forces and for allowing removal of said coupling piece from said lower container corner fitting by guiding said coupling piece away from said catch receiving surface upon applying upward force on said coupling piece.