TOKYO -- The Japanese arm of U.S. hamburger chain Wendy's will purchase Suntory Holdings' fast-food unit First Kitchen this summer, taking the opportunity afforded by McDonald's weak footing to expand its presence here.

Wendy's first tried penetrating this market in 1980, but was forced to pull out in 2009 after losing a price war to competitors, including McDonald's Japan. Wendy's made another attempt in 2011 through its establishment of Tokyo-based Wendy's Japan. But after opening three restaurants, it cut its store count down to one amid poor profitability. Not only was the competition stiff, but securing good locations proved difficult for a latecomer.

Meanwhile, First Kitchen operates 135 sites, many of them in choice Tokyo districts like Shinjuku and Akasaka. Suntory, for its part, aims to focus its strategy on liquors and soft drinks, President Takeshi Niinami said. In 2014, the Japanese beverage giant bought American distiller Beam in a deal worth $16 billion, and this spring it is selling off an equity stake in a sandwich chain.

On Monday, First Kitchen told domestic franchise owners that the chain will keep its brand even after Wendy's begins its takeover in July. Last year, a feasibility study was launched that converted two First Kitchen locations into establishments operating under both brands. The restaurants ended up increasing customer traffic by 20%, with couples figuring heavily in the result. Wendy's meaty menu items drew men while First Kitchen's desserts attracted female customers.

The successful pilot program sold Wendy's on the First Kitchen acquisition. A number of restaurants in Tokyo's city center will likely carry both menus, with the sites to be chosen based on customer demographics and location.

Wendy's move follows that of Shake Shack, a U.S. upstart that opened its first Japanese outlet in November. Carl's Jr., another American rival, re-entered Japan this March. Ned Lyerly, who heads the international division of operator CKE Restaurants Holdings, indicated the possibility of 1,000 Carl's Jr. restaurants in Japan.

Lyerly pointed to McDonald's struggles in the Japanese market as one driver of the decision. McDonald's Holdings (Japan) is seen controlling roughly 70% of the domestic hamburger chain market. However, same-store sales at all McDonald's locations in Japan fell 15% to 376.5 billion yen ($3.44 billion) in the fiscal year ended in December. Due to foreign objects found in food, among other scandals, the group lost about 70 billion yen in sales, about as much as a midsize chain would generate.

However, the Japanese market will likely hit a medium- to long-term growth ceiling because of the country's declining population, though the market currently is trending slightly upward due in part to the rise of dual-income families, according to the Tokyo-based Japan Foodservice Association.

MOS Food Services, the second-largest burger chain in Japan, sees domestic same-store sales inching up 1% in the current fiscal year ending next March, a level of growth that Managing Director Eisuke Nakamura says will be challenging to maintain. Wendy's renewed market push may spark an even greater struggle over a shrinking pool of restaurant-goers.