The case analysis in this paper leads to the necessity of direct
control mechanism for key parts and materials across the entire
supply chain. The required functions are monitoring all the
suppliers in the entire supply network, managing the total supply
chain inventory, securing the sustainability of key part/material
suppliers, and standardizing key parts/materials and production
methods. These functions are not in the conventional framework
of supply chain coordination mechanism of Toyota Production
System. However, it has become increasingly important to incorporate
direct control to execute these functions, at least for
electronics components.