Zentmeister
Did Itami consider the fact that the Germans have got their hands on everything she sells the Ming, probably figured out how to reproduce it, and will be more than happy to replace her as Ming's supplier for these goods. Even if they have to work at a loss due to higher labor and shipping costs.. because it completely Isolates Japan. This way Japan has no international trading partners, and all its merchant ships can be categorised as navy ships, allowing Berengar to do unrestricted submarine warfare.