PURPOSE: To prevent reduction in the mass of a platelike bullion of gold or a gold alloy as an important standard for judging the value of the noble metallic bullion in a circulation stage by cutting a discriminating display such as recesses having fixed intervals, a pattern or letters in each side of the bullion to prevent forgery.
CONSTITUTION: A rolled material 1 of gold or a gold alloy having fixed thickness and width is cut to obtain a bullion 2 whose mass is slightly larger than the prescribed mass. The edges 4 and the vertexes 5 of the bullion 2 are chamfered to form chamfered faces 6 while regulating the mass to the prescribed mass. A discriminating display 8 such as recesses having fixed intervals, a special pattern or letters is cut in each principal side of the chamfered four sides. The surface of the bullion 2 is then marked with the symbols of the component, purity and mass, a manufacture's sign, etc.
YAMAMOTO HIRONOBU
AKIYAMA TADAO
MATSUI SHIYOUICHIROU
