While the U.S. and Japan are stepping up political pressure on China to float its currency, some economists are asking if that's really the right policy.

An undercurrent of concern in Japan's financial corridors is that any sharp appreciation of the yuan against the yen could hit Japanese industries and the nation's stagnant economy.

Chinese leaders insist they are in no hurry to float the yuan. But if China conducts an upward revision of its currency, which has been pegged at around 8.30 to the dollar for the past nine years, it would drive up production costs at Japanese plants in China, eventually eating into corporate profits.