Nikkei press reported 2015 frozen food market share in Japan. According to it, the top supplier was Nisshin (43%).
Figure: 2015 Frozen Food Market Share in Japan
|Manufacturer||Market share (%)|
|Maruha Nichiro Seafoods||22.2|
Source is Nikkei Sangyo Shimbun newspaper, the article on 2016 July 25th.