Tokyo Japan -- Japan Post Network Co., Ltd. (Head office Chiyoda-ku, Tokyo, Japan; Chairman & CEO: Koji Furukawa) and Otsuka Pharmaceutical Co., Ltd. (Head Office: Chiyoda-ku, Tokyo, Japan; President: Taro Iwamoto) have announced distribution of special Heartfelt Summer Letter packs of powdered Pocari Sweat with space for a personal message, designed to be sent through the post as a summer greeting. Priced at ¥160 (tax inclusive), Pocari Sweat Heartfelt Summer Letter packs will be distributed through approximately 7,000 post offices in Japan between June 15 and August 31, 2010, with predicted sales of 150,000 units.