North Korea’s claim to have tested a miniaturised hydrogen bomb, which would represent a big advance in its strike capability, could lead to renewed calls for countries in the region to enhance their missile defences, changes that China opposes.

Analysts and military attaches say Beijing will be watching closely for signs that the United States and Japan are exploring improved ballistic missile defence, or whether Washington leans more heavily on South Korea to adopt its advanced high-altitude missile system, technology Seoul has so far turned down.

There is considerable doubt over the veracity of Pyongyang’s assertion that Wednesday’s explosion was a full-fledged test of a hydrogen device, but it could mark an advance in the secretive state’s nuclear technology.

… Richard Bitzinger, a security analyst at Singapore’s S. Rajaratnam School of International Studies, said North Korea’s actions potentially provided a “fig leaf” rationale for Japan to buttress its defences against its bigger security worry, China.