Japan's visit to North Korea comes after broad regional agreement that Pyongyang should not be offered talks unless it displays a genuine commitment to denuclearization.
In the wake of the North Korean attack on a South Korean island, the sense among many Koreans is they could carry on as usual. But some warn against complacency.
Seoul rejected Pyongyang's explanation that water levels had risen dangerously, pointing out that no recent downpours could have caused that. The water row is escalating just as tensions between the two had begun to ease.