Copper is often known as "Dr Copper" because of its uncanny ability to signal the health of the global economy. But in the light of this week's huge moves in the Yen, and in Japanese equities, Fridays Factoid is this: In the last 30 years, no single indicator has done a better job of predicting when the next global recession will start, than when the Bank of Japan starts raising rates:

Source: BAC Research