Japanese government bond yields hit a 25-year high, pushing the global arbitrage chain into a corner. The calm in U.S. Treasuries next door feels eerie. Japanese funds used to be big buyers of U.S. Treasuries, but now that domestic interest rates are rising, why would they still buy from outside? If this logic breaks, who’s going to take over the massive U.S. debt? The Bank of Japan is about to make an interest rate decision, and the entire market is betting: will they grit their teeth and hike rates, or keep holding on? Will this be the first domino to topple the calm in the bond market?