Abstract: North Korea claims to have detonated a hydrogen bomb twice as of 2017. While any North Korean claim should be greeted with skepticism, it is important to assess whether North Korea actually has the technical capacity to deliver on its claims. If North Korea believes that it has the capacity to build a hydrogen bomb, this is likely to color its behavior and its negotiating strategy with the United States and other countries. Using new data about research subject areas and co-authoring networks taken from North Korean academic journals, we can gain entrée into the opaque North Korean scientific establishment, and the progress (or lack thereof) it has made in processes related to the development of different types of nuclear weapons. We argue that a core group in North Korea has long had an interest in scientific research on lithium industrial processes that would be relevant to hydrogen bombs, although with detours. This interest has been ongoing since the mid-1990s, and peaked several years before North Korea’s first claimed hydrogen bomb test. Based on this assessment, it is within North Korea’s capability to produce a boosted fission device, and possibly a two–stage thermonuclear device. As a result, we conclude that North Korea is likely not bluffing when it says that its nuclear program has reached maturity. Full text available here.