Yen

Think about it, do you know of any wealthy acquaintance that has yen-denominated cash deposits? Dollars, euros, pounds, Swiss francs, even Singapore dollars, yes, but no one holds the currency of the world's second-largest economy. This arrangement is not viable in the longer term. To quote JK Galbraith, the Canadian-American Keynesian economist: "The enemy of the conventional wisdom is not ideas but the march of events."