Yesterday was a macro “risk -off” day as fears that currency and debt issues for emerging economies might spread widely enough to jar world economic growth. Commodities were hard hit by concerns that an economic slowdown would shrink demand for raw materials. Today turned into a “risk-back-on” day as weak currencies strengthened, world stock markets turned up and the worst-hit commodities like copper and crude oil recovered. Into this more favorable environment came an announcement in Beijing that a Chinese delegation, headed by the vice minister of commerce, would go to Washington next week for trade discussions with U.S. officials. The Chinese described the intended meeting as “high-level.” U.S. officia...