NTT Communications, Ltd.(http://www.ntt.com/index-e.html) DoCoMo Engineering inc. http://www.docomo-e.co.jp/global/conduct.htm Silver Star Japan Co., Ltd. http://www.silverstar.co.jp/ Instruction on networks by Japan Go Association http://www.nihonkiin.com/ Magnolia Co., Ltd.(http://www.magnolia.co.jp) (in no particular order)