The violent fluctuations of the Japanese yen through the 1980s and 1990s have played a critical role in Japan's economic decline. Brendan Brown highlights the causes of the yen's bizzare behaviour, and analyses the consequences for the Japanese and global economies. Through this analysis he presents an original hypothesis, linking the periodic sharp upswings of the Yen to poor economic performance and offers a new view as to where the responsibility for failure of the Japanese currency market to function normally lies.