A packaging for liquids is made of a flat packaging material. This material has fold lines (6) and a mark (11) placed on a wall area of the packaging. The invention also relates to a blank and to a method for producing a packaging of this type, in which fold lines (6) and the mark (11) are placed in a moving packaging web of material. Afterwards, the web of material is shaped, filled and closed. The aim of the invention is to simplify the production of the packaging and to provide it with a more economical and more precise design. To this end, the invention provides that the mark (11) is formed by stamp lines (25), which lie on a plane and of which at least two straight stamp lines (25) intersect at least in the extension thereof. It is advantageous when the mark (11) has at least one centra-symmetric structure. According to the method, the invention provides that the mark (11) is made by the placement of stamp lines (25) so that the cross-section of the material is U-shaped after stamping, whereby the thickness of the material remains essentially the same.