My speculations:
Maybe a soothsayer told him to do so. Japan starts to get hit by earthquakes a lot, their capital assets then get damaged, they then need repair/rebuild money, and so then, they dump their treasuries, later too. Frontrunning these events would be better, ya think!
Plus, the price of fish will skyrocket due to massive fish kills, and the Japanese love fish and eat a lot of fish. They need to convert their treasuries into cash to buy more higher-priced fish, ya think!
