When meeting the following various requirements, the special 2nd charge would be applicable from piece second of each packing type.
The delivery destination in Japan is one. (Basically become home or a parents' family. )
The one with heaviest actual or Volumetic weight would become the first charge application.
<Air Freight Volumetic>
Length (cm) x Height (cm) x> Width (cm) / 6000 = Volumetric Weight in KGS