Alternative to just buying government bonds

Nowadays Japanese yen is going higher,but stock market is not active. This phenomenon is curious in the world. What is this means? Who buy the Japanese yen? I think this is Japanese banks and funds who buy Japanese governmental bonds that raise Japanese yen. But this investment strategy is also strange because the Japanese stock market is not active in these days. If Japanese funds and banks start to invest in foreign growing area or stock market in Asia growing countries, then they can get returns and also the excessive yen will go down properly. Why this rational investment do not start?