'50XX': The Numbers North Korea Fears Most

North Korean leader Kim Jong Un criticized the South Korea-U.S. joint military exercise "Ulchi Freedom Shield (UFS)" on August 18 last year as the most hostile expression toward North Korea, declaring his intent to strengthen nuclear capabilities. Two days later, Kim Yo Jong, Deputy Department Director of the Workers' Party of Korea, issued a sharp condemnation, stating the exercises aimed "to eliminate our nuclear and missile capabilities early through invasion war drills and expand attacks into our territory."

On August 23, a spokesperson for the Korean People's Army General Staff issued a statement through the Korean Central News Agency, threatening to respond by exercising the right to self-defense, calling the UFS exercises "extremely provocative." The statement denounced "various training exercises where regiment-level and above forces and mechanized strike groups are organized in attack formations, maneuvering and conducting live-fire drills according to war scenarios" as "extremely provocative and aggressive large-scale combat exercises." This statement was also published in the Rodong Sinmun, the Workers' Party organ newspaper read by North Korean citizens.

Kim Jong Un, Kim Yo Jong, and the KPA General Staff all specifically targeted "OPLAN 5022" of the South Korea-U.S. military authorities in their successive criticisms. Analysts suggest the North Korean military leadership reacts so sensitively to regular joint exercises because approximately 40 large-scale outdoor maneuver drills are conducted during the training period.

OPLAN 5022, which contains plans to neutralize North Korea's nuclear attack capabilities early, is a new operational plan by the Combined Forces Command that replaces the existing OPLAN 5015. It was newly established after approximately 10 years and was agreed upon and signed by South Korea and the United States in 2024. These operational plans (OPLAN-Operation Plan) are military operation plans jointly established by South Korea and the United States to prepare for contingencies on the Korean Peninsula. Large-scale joint exercises have been conducted based on these plans.

The South Korea-U.S. combined operational plans that North Korea guards against most are classified as Level 2 secrets, and the military has never officially announced them publicly. They are typically referred to internally and externally as "OPLAN 0000."

The most representative is OPLAN 5022, which North Korea criticizes annually. This operational plan prepares for full-scale war with North Korea, with the concept of South Korean forces holding North Korean troops at points 20-30 kilometers south of the demilitarized zone while U.S. forces are reinforced and reorganize their formations for counterattack. The original designation was OPLAN 5027. Established in 1974, OPLAN 5027 evolved through versions including "5027-74" covering forward deployment of military forces on the Korean Peninsula during contingencies, "5027-92" assuming northward operations and siege of Pyongyang, and "5027-98" including preemptive strikes on Yongbyon nuclear facilities.

However, a September 2016 military internal network hacking incident leaked the Level 2 classified OPLAN 5027 externally, making modifications unavoidable. The result was the newly established OPLAN 5015. OPLAN 5015 incorporated the concept of preemptive strikes that simultaneously counterattack while eliminating North Korea's weapons of mass destruction including nuclear weapons and missiles. While OPLAN 5027 was U.S.-led, OPLAN 5015 differs in being South Korea-led.

From 2022, work proceeded on significantly revising the existing operational plan (5015), and a new operational plan was established in 2024 after approximately 10 years. OPLAN 5022 is known to supplement response measures against North Korea's more advanced nuclear and missile capabilities compared to previous plans. It is reported to be the first combined operational plan prepared by South Korea and the United States after North Korea declared completion of its nuclear force in 2017, recognizing North Korean nuclear weapons as a realistic threat.

The plan reportedly includes all scenarios: expanding the "kill chain" concept of detecting enemy missile launch indicators in advance and eliminating them before launch to mobilize all cyber and space capabilities to neutralize related capabilities early when North Korea's nuclear attack intent is identified, along with preemptive attacks, leadership elimination, territorial occupation, and stabilization operations after victory.

OPLAN 5026 is a precision strike operation against nuclear bases preparing for contingencies such as North Korean provocations. The core is simultaneously striking more than 1,000 targets by deploying fighter-bombers and bombers capable of dropping precision-guided bombs, particularly Joint Direct Attack Munitions (JDAMs), to destroy strategic targets within North Korea.

The plan reportedly includes launching Tomahawk cruise missiles from warships and nuclear-powered submarines and three-dimensional operations utilizing aircraft carriers. This is one of America's Korean Peninsula war strategies involving localized bombing to prevent escalation to full-scale war—a "surgical strike" concept for precision strikes on North Korean nuclear facilities.

U.S. Air Force assets are fully mobilized for this purpose. The main forces include F-15E fighter-bombers, B-1B and B-52 long-range bombers, F-22 stealth fighters, and B-2 stealth long-range bombers. B-1B and B-52 aircraft are pre-positioned in Guam, while F-22s deploy from the 49th Wing on the U.S. mainland or are stationed at Kunsan Air Base in South Korea. Two to four B-2 stealth bombers are inserted first to commence attacks.

This operational plan's characteristic is that it is a strategy for precision bombing of North Korean nuclear facilities using only South Korean forces and U.S. forces stationed in Northeast Asia before reinforcements arrive on the Korean Peninsula.

OPLAN 5028, a plan to eliminate North Korean military leadership including Kim Jong Un, is also a secret operational plan shrouded in secrecy. Completed for review in 2017, this plan reportedly includes special forces insertion and cover bombing in case of accidental North Korean provocations. Military experts view the special forces insertion and cover bombing as likely part of a unilateral U.S. "decapitation operation."

While OPLAN 5015 also includes the decapitation operation concept, experts generally view it as a combined South Korea-U.S. operation, whereas OPLAN 5028 is likely a unilateral U.S. operation.

OPLAN 5029 prepares for sudden changes in North Korea. During the Kim Dae-jung administration, South Korean and U.S. defense ministers agreed to establish strategic guidelines for responding to sudden changes, and it was made into a conceptual plan, but the Roh Moo-hyun administration suspended follow-up discussions citing potential sovereignty infringement. It was later elaborated during the Lee Myung-bak administration.

OPLAN 5029 established response measures assuming six situations: North Korean regime change, coup or civil war, risk of WMD seizure and removal, mass defection, major disasters, and South Korean hostage situations within North Korea.

OPLAN 5030, sometimes called "Operation to Exhaust North Korea," also exists. Reportedly established under Defense Secretary Donald Rumsfeld's direction during the George W. Bush administration, its core is allowing regional commanders to create conditions for North Korean regime collapse through low-intensity operations even before military conflict.

Preliminary operations included measures to deplete North Korean resources and induce military unrest. Examples mentioned include repeatedly flying reconnaissance aircraft near North Korean airspace to induce North Korean fighter scrambles and increase fuel consumption. Non-traditional tactics such as financial system disruption and false information dissemination are also reportedly included. This plan was designed considering North Korea's political and economic situation in the early 2000s.

U.S. OPLANs are distinguished by four-digit numbers according to the planning command. The 1000 series is U.S. Central Command, 2000 series is U.S. Northern Command, and reportedly exists up to the 9000 series. Korea-related operational plans, established by U.S. Indo-Pacific Command, begin with the 5000 series.

A notable point is that even if wartime operational control transfers from U.S. to South Korean forces, in the event of full-scale war with North Korea, the war will likely be conducted with South Korean forces supporting under U.S. Indo-Pacific Command-led operational plans.