Diecasting die system

A diecasting nozzle system (10) for use in a hot-chamber system (1) for the diecasting of metal melt (4), comprising a hot-chamber diecasting machine (2) with a casting vessel (3) and a melt distributor (20), which distributes the metal melt (4) uniformly from a machine nozzle (7) among heated diecasting nozzles (40), wherein at least one nonreturn valve (48) is arranged between a sprue region (42) of the diecasting nozzles (40) and the casting vessel (3), wherein said at least one nonreturn valve (48) prevents the metal melt (4) from flowing back from the sprue region (42) in the direction of the casting vessel (3), such that said at least one nonreturn valve prevents retraction of the liquid metal melt from an upper diecasting nozzle and at the same time the flow of the liquid metal melt out of a lower diecasting nozzle due to gravity, characterized in that the at least one nonreturn valve (48) is respectively arranged between the sprue region (42) of at least one upper diecasting nozzle (40) and a final branch of melt runners (22) in the melt distributor (20) to each of the respective diecasting nozzles (40).