Japan BitCash are strictly for Japan Games only.
BitCash is one of Japan's E-money used for online payment for Japanese online services, online games, SNS, video and music downloads. Japan BitCash Gift Card is a safe and easy-to-use Internet cash in the form of prepaid cards.
BitCash official website is https://bitcash.jp. Example supported games are Ameba, Mobage, DMM,etc.