[Yang Nak-gyu's Defence Club] The Timing of North Korea's Nuclear Test as Seen by South Korea, the US, and Japan

On the 24th, officials from North Korea's Nuclear Weapons Research Institute carried out demolition work to close the Punggye-ri nuclear test site in Kilju County, North Hamgyong Province. At the moment of the demolition of the Punggye-ri nuclear test site control command facility, wooden buildings were blown apart and shattered. On this day, seven control command facility buildings were demolished. Officials from North Korea's Nuclear Weapons Research Institute explained that "Tunnel No. 4 was prepared for the most powerful nuclear test." /

[Asia Economy Yang Nak-gyu, Military Specialist Reporter] The United States, South Korea, and Japan have expressed differing opinions on the possibility of North Korea conducting a nuclear test during President Joe Biden's visit. While the U.S. and Japan have raised the possibility of a nuclear test, the South Korean government views the likelihood as low.

Jake Sullivan, U.S. National Security Advisor, said during a briefing on the 18th (local time), "We have clear intelligence indicating the possibility that North Korea may conduct additional missile launches, including long-range missiles, or a nuclear test during or after President Biden's visits to South Korea and Japan."

Hirokazu Matsuno, Japan's Chief Cabinet Secretary, mentioned the possibility of a North Korean nuclear test for the first time. At a regular press conference that day, when asked about the possibility of North Korea conducting a nuclear test, Matsuno stated, "I believe there is a possibility of additional provocations, including a nuclear test, in the future."

On the other hand, the South Korean government's assessment differed. Kim Tae-hyo, First Deputy Director of the National Security Office, stated that while the possibility of a nuclear test by the weekend is relatively low, an intercontinental ballistic missile (ICBM) launch is considered imminent.

Although there are subtle differences regarding the timing of a nuclear test, North Korea experts believe the possibility of a nuclear test during Biden's visit to South Korea remains sufficiently high.

North Korea conducted its fifth nuclear test on September 9, 2016, immediately after former President Barack Obama attended the ASEAN summit in Laos and returned. Recently, North Korea has been conducting tunnel excavation work at Punggye-ri. In 2018, North Korea blew up the entrance to the underground nuclear test site at Punggye-ri, but it is now understood that tunnels have been dug below the entrance, connecting to the main tunnels.

If North Korea proceeds with a nuclear test, there are expectations that the U.S. strategic weapons could respond by raising the level of deterrence through threat flights and other measures. The strategic weapons expected to be deployed include the U.S.'s three major long-range bombers: the B-52H (Stratofortress), B-1B (Lancer), and B-2 (Spirit).

In September 2017, immediately after North Korea's sixth nuclear test, the U.S. flew two B-1B strategic bombers, known as the "Death Swans," and F-15C fighters into international airspace over the East Sea north of the Northern Limit Line (NLL). At that time, U.S. bombers and fighters flew farther north than any other aircraft beyond the Demilitarized Zone (DMZ).

Defense Minister Lee Jong-seop also held a phone call with U.S. Secretary of Defense Lloyd Austin on the 18th, marking their first conversation since Lee's appointment, to discuss measures to maintain a strong combined defense posture. Minister Lee emphasized the importance of deploying U.S. strategic assets in this context.