North Korea has alarmed the international community with a flurry of missile launches, and now appears to be preparing to resume nuclear tests. Some experts believe Pyongyang's quest for enhanced military power is a result of the conflict in Ukraine, which has caused a split at the United Nations Security Council, and reaffirmed Pyongyang's conviction that nuclear weapons are essential for deterring an attack by a stronger power. Others suggest leader Kim Jong Un sees military might as key to forcing the US back to the negotiating table. NHK asked a series of experts what the world can expect from Pyongyang in the months and years ahead, and what role Japan can play in an increasingly fraught situation. Guest: Isozaki Atsuhito (Professor, Keio University)