The SY (Chinese: 上游; pinyin: Shàngyóu; lit. 'Upstream'), and HY (Chinese: 海鹰; pinyin: Hǎiyīng; lit. 'Sea Eagle') series were early anti-ship cruise missiles (ASCM) developed by the People's Republic of China from the Soviet P-15 Termit missile. They entered service in the late 1960s[2] and remained the main ASCMs deployed by the People's Liberation Army Navy through the 1980s. The missiles were used by the PRC and export customers to develop land-attack missiles.[3]

SY/HY missiles
SY-1 missile
TypeAnti-ship cruise missile
Place of originChina
Production history

The name Silkworm is popularly used for the entire SY and HY family. As a NATO reporting name, it applies only to the land-based variant of the HY-1.[4]

Development edit

HY-2 missile
HY-3 missile

Chinese preparations were underway before receiving the first P-15s and related technical data from the Soviets in 1959. On 8 October 1956, the Fifth Academy was founded - with Qian Xuesen as director - to pursue missile development, and in March 1958 a cruise missile test site was selected at Liaoxi in Liaoning. The first successful missile test was conducted in November 1960 after the withdrawal of Soviet advisors in September due to the Sino-Soviet split. The P-15 was copied to become the SY-1. Production started at the Nanchang Aircraft Manufacturing Company in October 1963 and the first successful test occurred in 1965; production was approved August 1967 and the SY-1 entered service by the end of the decade.[2]

The SY-1 was developed into the improved HY-1; the HY-1 was successfully tested in December 1968 and entered service in 1974.[5]

Operational history edit

Iran–Iraq War edit

The Silkworm gained fame in the 1980s when it was used by both sides in the Iran–Iraq War; both countries were supplied by China. During 1987, Iran launched a number of Silkworm missiles from the Faw Peninsula, striking the American-owned, Liberian-flagged tanker Sungari and U.S.-flagged tanker Sea Isle City in October 1987.[6] Five other missiles struck areas in Kuwait earlier in the year. In October 1987, Kuwait's Sea Island offshore oil terminal was hit by an Iranian Silkworm, which was observed to have originated from the Faw peninsula. The attack prompted Kuwait to deploy a Hawk missile battery on Failaka Island to protect the terminal.[7] In December 1987, another Iranian Silkworm was fired at the terminal, but it struck a decoy barge instead.[8] Prior to these attacks the missile's range was thought to be less than 80 kilometres (50 mi), but these attacks proved that the range exceeded 100 kilometres (62 mi) with Kuwaiti military observers seeing that the missiles originated from the area and tracking them on radar along with US satellite imagery of the launch sites.[9]

Persian Gulf War edit

On February 25, 1991 during Operation Desert Storm, a shore-based Iraqi launcher fired two Silkworm missiles at the USS Missouri which was in company with the USS Jarrett and HMS Gloucester. A Sea Dart missile from HMS Gloucester shot down one Silkworm and the other missed, crashing into the ocean.[10] Royal Air Force officers subsequently recovered an HY-2 missile at Umm Qasr in southern Iraq. It is currently displayed at the RAF Museum Cosford.[11]

Iraq War edit

During the 2003 invasion of Iraq, Iraq used the Silkworm (HY-2 Seersucker) as a surface to surface missile by firing at least two of them at the coalition positions in Kuwait.[12]

Variants edit


License produced version of the P-15 Termit.[2] SY-1A variant is upgraded with monopulse seeker and radar altimeter enabling a sea-skimming profile[13] NATO reporting name CSS-N-1 Scrubbrush.[1]


A development of SY-1A propelled by solid-fuel rocket sustainer. It forgoes its predecessor's pre-launch fueling process and is smaller, lighter, and longer-ranged (50 km). As the weapon has comparable range to the more-advanced YJ-8A but can use existing launchers and logistical equipment for the SY-1, it entered service to arm some frigates built during the 1990s as well as frigates built prior.[14][1]


Essentially a scaled-up SY-1 to extend range to 70 km for coastal defense and, later, warship use. NATO reporting names CSS-N-2 Safflower(ship-based) and CSSC-2 Silkworm (land-based).[1] It saw only limited deployment with coastal artillery units before being superseded by the HY-2 but remained in use as the main anti-ship armament of the 051 class destroyers. HY-1A variant is upgraded with improved conical scan seeker and radar altimeter enabling a sea-skimming profile.[15]


A parallel development with HY-1 with a range of 95 km, achieved by redesigning internal layout to enlarge fuel tankage and adopting a more-efficient rocket sustainer. NATO reporting names CSS-N-3 Seersucker(ship-based) and CSSC-3 Seersucker (land-based). Only land-based version is mass-produced.[1] HY-2B variant is upgraded with monopulse seeker and radar altimeter enabling a sea-skimming profile.[16]


Unsuccessful supersonic design.[17][18]


Powered by a WP-11 turbojet, a reverse-engineered Teledyne-Ryan J69-T-41A.[19] Used for LACM development.[20] NATO reporting name Sadsack.[21]


Air-launched LACM sharing visual characteristics of the HY-2, HY-4, and YJ-6. 200 km range.[19]


Longer-ranged variant of the HY-2 developed by North Korea.[22]

Operators edit

Map with Silkworm operators in blue

Current operators edit

References edit

  1. ^ a b c d e f Gormley, Erickson & Yuan 2014b, p. 113.
  2. ^ a b c Gormley, Erickson & Yuan 2014b, p. 9.
  3. ^ Gormley, Erickson & Yuan 2014b, p. 28.
  4. ^ Gormley, Erickson & Yuan 2014b, p. 135.
  5. ^ Gormley, Erickson & Yuan 2014b, pp. 9–10.
  6. ^ "U.S. Flag Tanker Struck by Missile in Kuwaiti Waters; First Direct Raid". The New York Times. October 17, 1987.
  7. ^ "The Gulf Punch, Counterpunch". Time.
  8. ^ "Iranian Silkworm strikes decoy barge"; Daniel J. Silva. St. Petersburg Times. St. Petersburg, Fla.: December 8, 1987. p. 14.A.
  9. ^ Counter-memorial and Counter-claim submitted by the United States of America Archived 2014-03-31 at the Wayback Machine. June 23, 1997.
  10. ^ Rostker, Bernard (December 2000). "TAB H – Friendly-fire Incidents". Depleted Uranium in the Gulf (II). United States Department of Defense. Archived from the original on 2013-06-01. Retrieved 2007-02-25.
  11. ^ "Hai Ying 2G Seersucker". RAF Museum. Retrieved 17 May 2014.
  12. ^ "Center for Defense Information". Project On Government Oversight. Archived from the original on December 23, 2003.
  13. ^ "中國反艦導彈系列". MDC軍武狂人夢.
  14. ^ "中國反艦導彈系列". MDC軍武狂人夢.
  15. ^ "中國反艦導彈系列". MDC軍武狂人夢.
  16. ^ "中國反艦導彈系列". MDC軍武狂人夢.
  17. ^ "中國反艦導彈系列". MDC軍武狂人夢.
  18. ^ Gormley, Erickson & Yuan 2014a, p. 102.
  19. ^ a b Gormley, Erickson & Yuan 2014b, p. 29.
  20. ^ Gormley, Erickson & Yuan 2014b, p. 27.
  21. ^ Gormley, Erickson & Yuan 2014b, p. 84.
  22. ^ "KN-01 (Silkworm/Styx)". Missile Threat. Center for Strategic and International Studies. 31 July 2021. Retrieved 7 July 2022.

Sources edit

External links edit