This paper addresses issues in supply chains of natural materials in the automobile parts manufacturing sector. Problems unique to the supply chain of natural materials for steering wheel manufacturers are examined with improvements explored and solutions offered. Automobile parts suppliers are forced to cope with fluctuations of demand from downstream. However, suppliers using natural materials need to respond to additional fluctuations of supply in material from upstream. This conflicting flow in the supply chain due to material differences has not hitherto been fully researched. This study focuses upon the problems faced by two Japanese automobile parts suppliers, one using bamboo and the other using leather. Interviews conducted on site reveal how the suppliers overcame key problems. The study suggests parts suppliers might be key to improving the supply chain of natural materials by optimizing inventories in the middle and functioning as a buffer.
