Major Japanese-style pub operator Watami Co. said Friday it has acquired the Japanese unit of the Subway sandwich chain for an undisclosed amount in an effort to diversify its business. The Tokyo-based operator of the namesake izakaya pub chain said the deal includes a franchise contract with Subway International B.V., based in Amsterdam, to operate Subway stores in Japan for the next 10 years. In 2023, Subway Japan G.K. posted 536 million yen ($3.5 million) in revenue, according to Watami. Watami said it plans to increase the number of Subway stores in Japan to over 3,000 from the current 178…