Published by Jamie JemmesonAlthough Japan's central bank is fighting continuously to curtail the appreciation of the yen against the dollar, one economist has sought to put the currency's rise in perspective.Writing for Seeking Alpha, Scott Grannis, who was chief economist of Western Asset Management from 1989 until 2007, explained that the rise of the yen should be examined in light of inflation and purchasing power parity."On that basis, in the mid-1990s the yen was far stronger relative to the dollar than it is today ... By my calculations, the yen today is only about 40 per cent 'overvalued' vis a vis the dollar," he explained.His comments followed another surge in the yen in global forex trading yesterday (August 30th), when the currency hit a 15-year high against the dollar.As the yen rose, the Bank of Japan called an emergency policy meeting to discuss the country's economic prospects, sparking speculation that the central bank would look to intervene directly to stem the rise in the currency.For more information on foreign exchange treasury services and risk management, visit our Corporate FX site.