Nikkei newspaper group estimated the 2015 convenience store market share in Japan. According to it, 7-Eleven is the largest chain in Japan.
Figure : Convenience Store Market Share in Japan, 2015
|Chain||Market share (%)|
|Circle K Sunkus||9.1|
Source is Nikkei Sangyo Shimbun newspaper, the article on 2016 July 25th.