China's plans for a tax on currency trading triggered an outcryof criticism about the potential hit to financial markets. Obscuredin the conversation is how the move shows again that the world'sNo. 2 economy isn't content with acceding to a global financialsystem crafted by No. 1.

No major economy has implemented a Tobin tax, a move thatbackers say would curb currency speculation that distortsexchange-rate values. The rules still need central governmentapproval, and it's not clear how quickly they can be implemented,according to people familiar with the matter. The initial levywould be kept at zero to allow authorities time to refine therules, and it wouldn't be designed to disrupt hedging and otherforeign-exchange transactions undertaken by companies, theysaid.

Onehope: A Tobin tax could help curb an outflow of funds from Chinathat last year reached a record $1 trillion. The idea followsChina's use of its leadership of the Group of 20 to examineproposals that would reduce the dollar's dominance. Otherevidence of China's desire to revamp global financial architecturehas been seen in its launch of development banks to rivalestablished lenders such as the World Bank.