On January 14 one of the present authors, Georgy Toloraya, participated in a roundtable discussion of Russian experts (political, military and technical) in Moscow hosted by Russia’s Rossiya Segodny Press Agency. The experts suggested that North Korea, on January 6, most likely detonated a boosted fission nuclear device allowing it to achieve a greater yield with lower consumption of nuclear material that could more easily be mounted to a missile.

Speaking from the political perspective, neither this step by North Korea nor the reaction from the international community is new or unusual. Most experts expressed the opinion that North Korea