KN-01 (Silkworm/Styx)

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The KN-01 is the U.S. designation for a North Korean antiship cruise missile. It is an extended-range variant of the Soviet Union’s P-15 Termit (also known as Styx and SS-N-2) and China’s HY-1/2 Silkworm.

KN-01 at a Glance

Originated from
China (CSS-C-2 Silkworm), Soviet Union (P-15 Termit/Styx/SS-N-1)
Antiship cruise missile
Possessed by
North Korea
Alternate name(s)
Kumsong-1, Geum Seong-1, AG-1
Road-mobile, air-launched
7.36 m
0.76 m
Launch weight
3,000 kg
Single warhead, ~500 kg
Solid propellant boost motor, liquid propellant sustainer motor
160-300 km

KN-01 Development

North Korea’s acquisition of the KN-01 came from a combination of imports from China and the Soviet Union, domestic production, and indigenous upgrades. North Korea acquired its first KN-01 type ASCMs from the Soviet Union in 1967, importing around 150 SS-N-2 (P-15U) “Styx” missiles between 1967-1970 and 9 units of the land-based SS-C-2 variant. The Soviets also provided training and maintenance support.1 In 1979, Pyongyang ordered another 120 SS-N-2s from the Soviet Union. The USSR delivered around 85 P-15Us to North Korea between 1981-1991, with Russia fulfilling the remaining 35 delivered in the early 1990s following the fall of the Soviet Union.2

North Korea also began also receiving imports of the Chinese version of the missile, HY-1 Silkworm, in 1970. By 1974, China had assisted Pyongyang in developing and maintaining a domestic production capability. In 1976 China began exporting the upgraded HY-2 version of the missile, delivering around 200 HY-2 missiles to North Korea between 1976-1982.3 North Korea may have also begun domestic production of the HY-2 during this period.4

In May 1997, North Korea test-fired an upgraded version of the HY-2, which Pyongyang designated the AG-1. The upgrades extended the missile’s range from 85 km to as much as 160 km.5 The United States designated this extended range variant the KN-01. In 2013, reports surfaced that North Korea may have added a turbojet engine to the missile to further extend its range, giving it a reach of up to 300 km.6


The KN-01 is 7.36 m in length and 760 mm wide and weighs around 3,000 kg at launch. It typically carries a 50 kg high-explosive (HE) warhead, with a range between 160-300 kilometers.7 Other reports suggest its range could be lower, at around 110 kilometers.8

Service History

The first North Korean deployments of the SS-N-2 North Korea were primarily ship-based aboard fast attack craft such as Komar- and Osa-class missile boats. The DPRK military has also deployed the missile in mobile, land-based launchers.

In 1988, the LA Times reported that North Korea exported 4-5 KN-01 type missiles to Iran, an assertion which North Korea denied.10

North Korean KN-01 coastal defense batteries played a minor role in the Second Battle of Yeongpyeong, a naval skirmish between North and South Korean navies in 2002. At one point in the engagement, North Korea activated KN-01/HY-1 associated targeting radars, which prompted the South Korean navy warship to employ chaff countermeasures and break off pursuit of several North Korean ships to avoid an escalation.11

North Korea test-fired an air-launched version from an Il-28 bomber on at least two occasions in 2011. Most recently, North Korea launched three KN-01s in June 2015.12 The missiles flew for around 26 minutes, to a range of 100 kilometers.

The importance of the KN-01 within North Korea’s military will likely wane as Pyongyang fields more advanced antiship missiles such as the Kumsong-3.


    1. Joseph S. Bermudez, “A History of Ballistic missile Development in the DRPK,” Occasional Paper No. 2, Center for Nonproliferation Studies (November 1999), 4.
    2. SIPRI Arms Transfer Database, “Trade Registers,” Stockholm International Peace Research Initiative, Accessed April 22, 2021,
    3. SIPRI.
    4. Joseph S. Bermudez, 4.
    5. “North Korea Missile Milestones,” The Wisconsin Project, accessed April 23, 2021,
    6. Kang Tae-jun, “North Korea extends range of KN01 anti-ship missile – media,” NK News, November 23, 2013,
    7. John Schilling and Henry Kan, “The Future of North Korea’s Nuclear Delivery Systems,” US-Korea Institute at SAIS, April 2015, 24,
    8. “HY-2 improvement (AG-1/KN-01),” in IHS Jane’s Weapons: Strategic 2015-2016, ed. James C. O’Halloran (United Kingdom: IHS, 2015), 166-167.
    9. John M. Broder, “Five Key Nations Sold Arms to Iran Last Year,” LA Times, January 20, 1988,;

      In the post-Cold War era, North Korea has used the KN-01 in multiple military parades and has frequently conducted flight tests. Between its first flight test in February 1993 and June 2007, North Korea has flown KN-01 missiles 10-15 times.9“HY-2 improvement (AG-1/KN-01),” in IHS Jane’s Weapons: Strategic 2015-2016, ed. James C. O’Halloran (United Kingdom: IHS, 2015), 166-167

    10. “North Korea Missile Chronology,” Nuclear Threat Initiative, Last updated January 2012,, 3.
    11. “N. Korea Test-Fires Three Short-Range Missiles,” Defense News, June 14, 2015,
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Missile Defense Project, "KN-01 (Silkworm/Styx)," Missile Threat, Center for Strategic and International Studies, August 8, 2016, last modified April 23, 2024,