Yuan Revaluation

China owns much of Yankee Bond anyway and with the Euro no longer a serious contender, Yuan is looking pretty hot to take over from the USD.  China is also dumping the US bigtimes. They've already dumped US$ 34 billion greenbacks onto the open market to reduce their risk/exposure  to the US bond market.  The funny thing is they were usually buyer of US Treasury bond so is it the sign of what?