OPLAN 5027 Major Theater War - West
Phase 2-ROK Defense
A favorable outcome for the South depends on two conditions. First, the ROK forces must withstand the DPRK attack during the initial 5-15 days of North Korean offensive actions. Second, they must hold the line while US and ROK forces are mobilized for the counteroffensive, which could take another 15-20 days. South Korea is likely to be able to successfully defend and repel a conventional DPRK along the demilitarized zone.
South Korea would appear to have outright superiority, as measured by these types of static indices, once one factors in the effects of superior training, equipment maintenance, logistics and support equipment like reconnaissance and communications gear (to say nothing of the advantage of fighting from prepared positions.) Quantifying the importance of these effects is difficult, but those who have attempted to do so have found impressive results.
ROK and US forces possess a noticeable technological advantage over DPRK forces. For the most part ROK forces would be facing increasingly outdated DPRK equipment using modern and well-kept equipment outfitted with current detection and targeting systems. The most modern pieces of DPRK armor showed its age in the 1991 gulf war (although terrain variations must be taken into consideration) and the most plentiful pieces were not particularly capable 35 years ago, let alone today.
The process of changing the reconnaissance posture for strategic and tactical warning of attack operated by ROK and US military forces is called the WATCHCON system. There are about 180 unusual North Korean military movements on the "Indication and Warning Lists" which are intensively monitored, based on the WATCHCON levels. The Watch Condition hierarchy is characterised by four stages: WATCHCON 4 (normal peacetime position), WATCHCON 3 (important indications of threat), WATCHCON 2 (vital indications of threat), and WATCHCON 1 (wartime situation). The WATCHCON is normally raised by the agreement of ROK and US military intelligence authorities.
In normal defense situations, the South Korean troops maintain Watchcon 3 surveillance status and Defcon 4 defense readiness status. When tensions rise, the status is upgraded, and in war, they are raised to Watchcon 1 and Defcon 1.
The ROK-US issued WATCHCON 1 from 19 February to 17 March 1982, in response to North Korean Air Force training and bombers deployment. WATCHCON 3 was issued respectively in the wake of North Korean nuclear problem in the spring of 1994, and Air Force training and aircraft deployment in October-November 1995. On 06 April 1996 more than 100 North Korean troops entered the northern sector of the Joint Security Area (JSA) at Panmunjom the day after North Korea announced it had "dismissed" the armistice with the South. Both ROK and US forces were put on a higher state of alert - Watchcon 2. The ROK Defense Ministry also upgraded its Watchcon 3 lookout posture to Watchcon 2 without consultations with the US military. There was no change in defense readiness, which was maintained at Defcon 4. The CFC reverted to Watchcon 3 several weeks after the April armistice violation. In June 1999, when a naval battle between South and North Korea took place, the first of its kind since the end of the 1950-53 Korean War, South Korean forces were put on Watchcon 2 surveillance status and Defcon 3 defense posture. The JCS issued an order of combat readiness equivalent to Defcon 3 around the five islands off the northwestern coast and ordered all Southern fishing boats to withdraw from the contested area. Simultaneously, it issued a Watchcon 2 surveillance order for all South Korean Armed Forces to heighten defense readiness in an escalation of the military crisis.
The North Korean avenues for attack are heavily defended by hardened, well-prepared ROK defenses. These forces are densely located along the demilitarized zone. The force-to-space ratio has been calculated at one division per 10 kilometers. Given these force-to-space considerations, the inability of DPRK forces to maneuver around the defending units in the DMZ, and the likely ineffectiveness of unconventional forces inserted behind the defender, DPRK forces are not likely to be able to quickly push through and create a breakthrough.
The South Koreans have a series of defensive lines that cross the entire peninsula, but with the exception of the South Barrier Fence, they aren't connected completely across the peninsula. They are designed to withstand an attack and allow a minimum force to hold a line while reinforcement/counter attack forces are assembled and sent to destroy any penetrations.
The Korea Barrier System (KBS) consists of tactical obstacles to support the defense of the Republic of Korea. It is an extensive, in depth, and integrated series of obstacles and barriers, including minefields, concertina wire, and dragon's teeth. The combat multiplication that the Korea Barrier System affords defending forces is fundamental to halting an attack north of Seoul with the forces currently available.
On the Northern side of the DMZ there are no defensive fortifications equivalent to Forward Edge of Battle Area (FEBA) A, B, and C in the South. FEBAs are concentric defense lines clearly observable south of the DMZ but not in the North.
The overwhelming majority of mine fields are in the General Outpost Line (GOPL) and the Forward Edge of the Battle Area (FEBA) areas, which are not accessible to noncombatants. Maintaining installed mine fields along the GOP allows ROK Army units to complete the defensive preparations of the remaining FEBAs in minimal time if hostilities occur. Planning is based on the premise that there will be 1-3 days' unambiguous warning of a North Korea attack. Without the existing mine fields being installed, there is no way that they could be installed in 24-72 hours.
Although most of the minefields that compose the Korea Barrier System have been installed by Republic of Korea forces, some have existed as far back as the Korean War. Infrequently, spring floods may move some of the landmines from the DMZ to outlaying areas. Occasionally casualties occur from mines inserted during the war but swept to unmarked areas near or within the DMZ. The ROK Ministry of Defense claims reports 155 people died of mine accidents between 1990 and 2000, including 75 civilians. In 2000, one soldier died and 12 were injured in landmine incidents in the DMZ and Korean Army bases. There were six civilian casualties in Korea including two children, none of the accidents occurred in acknowledged minefields.
Force-to-space ratios imply that there is a limit to the amount of force that can be brought to bear on a kilometer of front -- the "crossing the T" problem. Above a certain force-to-space ratio invading forces will have to be echeloned, which will makes them vulnerable to long-range interdiction. Furthermore, only a fraction of the firepower of the attacker can be brought to bear against the defenders, whereas defenders using long-range indirect fire weapons from shielded positions may cover a large frontage plus follow-up forces without being deployed at the FEBA (forward edge of battle area) at all.
Not all the North Korean forces may actually come into play, because of topography. With merely 238 km of border between the two Koreas, half of which is blocked by mountains. The topography of the DMZ is not conducive for rapid advance and gives defensive forces a further advantage. The channels of attack and predetermined bridge and road demolition planning can funnel attacking forces into focused ROK firing positions. This defensive advantage may be somewhat nullified by a winter assault, which would open up, though not completely, a larger number of avenues of approach.
While both sides have a large number of artillery pieces focused on the region, defensive forces would have an advantage over attacking forces. Hardened bunkers would protect defensive forces; attacking ROK forces would be exposed to artillery without the benefit of hardened positions. North Korea could use smoke and other vision impairing implements. These would likely be overcome by superior ROK and US reconnaissance aircraft radar systems which could provide a significant advantage.
Similarly, DPRK could use poor visibility due to natural weather conditions to help obscure visibility and reduce the effectiveness of reconnaissance aircraft. These conditions are unlikely to persist for more than several days. Using passing weather systems in this way is difficult to predict and impossible to sustain.
ROK and US forces possess a substantial air advantage over DPRK. Unless DPRK enjoys miraculous weather conditions that prevent adequate ROK or US sorties, Southern forces would likely be able to quickly establish air superiority over North Korean positions, further subjecting DPRK forces to allied fire. To counter the threat of ROK and US air power, DPRK forces would likely attempt to destroy southern air bases with initial missile salvos. Potential affects of such attacks would likely be limited.
Japan and the ROK are not party to a mutual defense treaty, and South Koreans still expressed concerns about renewed Japanese militarism. In a sense, remaining even mildly neutral about Japan denies a critical part of Korean identity. Security cooperation with Japan could be seen as subjugating Korea once again to Japanese domination. Nonetheless, the triangular alliance arrangements with the United States have created de facto security ties. These informal defense links were first publicly enunciated in the joint communiqué issued at the conclusion of the November 1969 Nixon-Sato summit. Known as the "Korea clause," it stated that the security of the ROK was essential to Japan. Concurrent with the enunciation of the Korea clause was the Okinawan base agreement, which stipulated that in the event of a second North Korea invasion, Japan would permit the United States unconditional access to bases in Okinawa for the defense of South Korea. Japan reneged on the Korea clause in the 1970s (Sato in January 1972 and Foreign Minister Ohira in August 1973 made statements backing away from commitments in the Korea clause and Okinawa base agreement).