Major convenience store chains, which have seen sluggish sales amid severe competition in a highly saturated market, are trying to diversify in a bid to mine more promising market segments.

99 (Kyukyu) Ichiba Co., an affiliate of major convenience chain Circle K Sunkus Co. and whose existing stores operate 24 hours a day and sell perishables, opened a new shop in Edogawa Ward, Tokyo, earlier this month similar to 100 yen shops.

Circle K Sunkus, the nation's fourth-largest convenience store chain, plans to open 100 of the shops in the Tokyo metropolitan area over the next three years, hoping sales will increase to about 13.7 billion yen.