After the collapse of the Bretton Woods system of fixed exchange rates and the eventual floating of currencies from 1973, the second amendment of the Fund’s Articles of Agreement in 1978 made its mandate more explicit by fixing its oversight over individual countries’ exchange rate policies.
As a result, they are proceeding with purchases of JGBs, particularly those with super-long maturities that are still offered with positive yields, and I think that this is one of the factors behind further tightening of the JGB market conditions and somewhat unstable conduct of the Bank’s JGB purchases.