Surely market participants would have noticed if the BoJ had been buying in the market. Or, perhaps BoJ was not buying in the market. Whatever the BoJ did do in its government securities account, however, it was sterilizing in operations elsewhere. Otherwise, the balance sheet could not have been stable on the month. The future is a different story, however.
Many Japanese investors remain enamored of the bond market.
It has certainly been moving their way and against the direction that I have been forecasting. The hole in the bond market for now is being filled. If so, then the effect is not likely to last. As with intervention in foreign exchange markets, changes in the composition of assets on the central bank's balance sheet should not change long-term interest rates. The theoretical possibility for such a change exists, if investors have habitats along the yield curve.