Government bond markets should be seen, but not felt. These giant pools of capital are meant to move slowly. Japan, home to one of the biggest and usually most boring of all, is bucking that trend with a peculiarly sharp rise in long-term borrowing costs. It’s a largely local story so far, but one investors elsewhere should pay attention to.

Rising rates on long-term bonds have been causing concern worldwide, as investors worry about high levels of government spending in slowing, ageing economies. Even so, Japan’s recent moves stand out. Yields on its 30-year bonds have risen 0.63 percentage points, almost twice as much as their US counterparts, in the weeks since President Donald Trump’s so-called “liberation day” tariff plans triggered global market turmoil. Germany’s equivalents are virtually flat over that time.