By the way, this recognition that trust is central, or even constitutive, for the properties of money is very old; it was already discussed in the 4th century BC by Aristotle in his Politics and Nicomachean Ethics.
Up until then, volatility in asset prices had been very low internationally, resulting in tighter credit spreads and smaller term premiums. With investors appearing "overly complacent" about asset price changes and various other risks, a situation developed in which investors focusing on the interest rate differential between Japan and abroad favored the yen carry trade.