Seiyu GK and U.S. parent Wal-Mart Stores Inc. will close about 30 unprofitable stores starting next year, the companies said.
The closure will affect about 10 percent of their 373 outlets in Japan. The companies did not specify which stores would be shut or when.
Seiyu and U.S. retail giant will focus their efforts on stores in good locations and will remodel about 50 outlets to offer a wider selection of fresh food and deli items.
They will also strengthen their online grocery business by expanding service areas.
Wal-Mart forged a capital tie-up with then-struggling supermarket operator Seiyu Ltd. in 2002 and put the Japanese retailer under its wing.
Six years later, Seiyu became a wholly owned subsidiary of the retailing titan but retained its brand. New stores have since been opened in such cities as Kobe and Sendai.
By prefecture, Seiyu and Wal-Mart run 77 outlets in Tokyo, followed by 72 in Fukuoka, 48 in Nagano and 30 in Saitama.