Are cryptocurrencies taxable in Japan?

Could you please elaborate on the taxation policies surrounding cryptocurrencies in Japan? Is there a clear framework for determining whether or not transactions involving digital currencies are subject to taxes? If so, what are the key tax implications for investors and traders? Also, has the Japanese government issued any specific guidelines or regulations in this regard? Understanding the tax treatment of cryptocurrencies is crucial for those considering investing in this market, so a detailed explanation would be greatly appreciated.