According to the early results from monitoring systems, whatever North Korea blew up probably wasn’t a hydrogen bomb. But there’s no doubt it was a major provocation that got the attention of world leaders.

+ WaPo: Why is North Korea’s hydrogen bomb test such a big deal? (And why it may have been an early birthday present for Kim Jong Un.)

+ NYT: “North Korea is just thumbing its nose at China. That’s got to produce a reaction.”