Japanese bond auctions next week may challenge US Treasury Secretary [PERSON_NAME]'s efforts to subdue longer-maturity Treasury yields. [ADDRESS] is selling 10-year bonds on Sept. 1 and 30-year securities two days later just as investors demand ever more compensation to fund governments around the world. Any sign of lackluster interest at the auctions risks spilling over to the Treasuries market, where 30-year [ADDRESS] yields are already near the highest levels in almost two decades.