Among many exchanges in the region of Japan, Bitflyer is exchange that has met all requirements to be called am internationalized exchange. Bitflyer is regulated in Europe, America and Japan. It is good to also note that Japan is highly strict in it's regulation of financial markets. Hence for Bitflyer to measure up to its stringent regulations, the exchange is good for all.
Recently this exchange already sealed an integration with PayPal which allows all users are f PayPal to easily trade digital assets on the exchange. This will go a long way to increase it's liquidity.
The exchange support Bitcoin, Bitcoin cash, ethereum and many other digital assets. It also support mobile trading.
Also there is no need to fear in terms of security because all opened end must have been tightened to measure up to the regulatory standard of those countries.