The earthquake that hit northwestern Japan on Monday, July 16 has shut down Riken Corp., a major supplier of piston rings and other parts to Japanese automakers.

As a result, four automakers including Toyota have been forced to suspend production. For Toyota that means halting work at all twelve of its parts and domestic car factories from July 19 through July 20.

Suzuki, Mitsubishi, and Fuji (the maker of Subaru vehicles) will also stop work at their facilities and Honda may be forced to follow suit next week.

Beginning today Suzuki will close down five factories including two car assembly plants for at least three days. Company spokesmen anticipate production losses of 5,000 motorcycles and 10,000 cars.

Three Mitsubishi plants will go off line and Fuji will shut down its mini-vehicle line through Saturday losing about 1,500 units.

Both Nissan and Mazda are evaluating their situation. Most of the automakers are seeking alternative sources for parts and are expected to make up for the production losses next week with longer work days.

Teikoko Piston Ring Co., NOK Corp, and Nippon Piston Ring Co. are expected to take up the slack in the parts supply chain.

Spokesmen from Riken could not say when production at their facilities would resume. Two piston ring factories and nine affiliated plants were either in or in the vicinity of Kashiwazaki, the city that received the greatest degree of quake damage.

Riken faces repositioning dislodged equipment, conducting quality and precision checks, and having its supplies of gas and water restored before it can come fully back online.