Why is the yen becoming a reserve currency?

The fall in the weight of the dollar in global foreign exchange reserves is counterbalanced by an increase in the weight of the renminbi and the yen. The weight of the yen is becoming significant (5.25%) and the yen is therefore becoming a real international reserve currency. This development is surprising: The Japanese economy is not decoupled from other economies, and invest ing in yen therefore does not mean invest ing in a country decoupled from the global cycle; Despite the zero interest rates, Japan is not fiscally solvent; The return on financial assets in yen is lower than on financial assets in dollars.