http://www.ngk-sparkplugs.jp/

NGK is the brand name of spark plugs sold by Japan Special Ceramics.
Nippon Special Ceramics Co., Ltd. (NGK Spark Plug Co., Ltd.) is a manufacturer of spark plugs and ceramic products. A member of the Morimura Group. Established in 1936. The head office is located at 14-18 Takatsuji-cho, Mizuho-ku, Nagoya City, Aichi Prefecture. The company operates worldwide and has an overseas sales ratio of over 80%.