On the margin these will cause issues for future issuance of JGBs "IF" they do not find buyers but yet again the buyers have been domestics time and again (thanks as always to QE). The exact same argument could be given every year for the past 10 years. They never did expect and would not expect foreigners to buy JGBs (they are not that naive). Why didn't asset managers sell JGBs then (when the yen was much weaker and confidence was at it lows compared to the rest of the world) and invest into higher yielding sovereigns elsewhere ? The CAB changing from surplus to deficit will impact the scene on the margin and yields will rise and if it comes to restructuring and write downs, the pain will be absorbed within and reallocated. They will still not be at the mercy of anyone outside. The real problem is with fiat currencies in general and not specific to Japan.