North Korea announced in November 2020 that it had completed deployment of its Kumsong-3 anti-ship missiles to naval bases and ships on both the east and west coasts. This new missile is intended to protect North Korea’s surface ships and submarines from hostile (South Korean, American and Japanese) warships. More test firing was to take place before the end of 2020 but so far that has not happened.
Kumsong-3 was first revealed in 2014 when North Korea released a video showing the missile. The first test firing took place in 2015 when one was launched from a patrol boat and observed landing 200 kilometers distant. During an April 2017 military parade in North Korea Kumsong-3 was shown mounted on a tracked vehicle, which carried four storage/launch cannisters side-by-side. A few months later one of these vehicles on the east coast fired four Kumsong-3 missiles. South Korea, the U.S. and Japan monitor both coasts for such launches and noted that these missiles travelled 240 kilometers.
It was obvious (from the pictures) that the missile was a Russian Kh-35 (also known as the SS-N-25 or Switchblade) that had earlier been seen on one or two of the four of five large (over 1,000 ton) surface warships the North Korean Navy has that were capable of going to sea, but rarely do. The 2017 test was from a mobile launcher and that was apparently the same one that had appeared earlier in the parade. The missile shown not only looked like a Russian Kh-35 and the data North Korea released showed it performing like a Kh-35, which Russia has been busy upgrading and marketing since the late 1990s.
The Kh-35 was the Russian response to the American Harpoon and development did not begin until 1983. Work was stalled with the collapse of the Soviet Union in 1991, which saw most of the defense budget disappear as well. Russia announced the Kh-35 was available for export in 1996 but the Russian Navy did not start using it until 2003 and that was about when export sales and deliveries began to happen. In 2006 Russia announced it had put into service a land-based version of Kh-35 that could be operated from fixed or mobile (trucks or tracked vehicles) launchers. This is what North Korea did with its Kumsong-3 in 2017.
By 2008 the Kh-35 could be fired from helicopters, aircraft, ships, or land. It is a 620 kg missile that used a rocket booster for launch and then switches to a small turbojet. The missile flies 10-15 meters above the water. When making its final approach to a target the missile drops to about four meters above the water. The earliest version had a range of 120 kilometers but the 2008 upgrade increased that to 250 kilometers. That increased Kh-35 weight to 670 kg. Russia sells them to export customers for less than a million dollars each.
Russia denies it sold the missiles to North Korea thus the only other likely source is one of the known foreign customers (Algeria, Azerbaijan, Burma, India, Iran, Venezuela, and Vietnam). Vietnam is building Kh-35 under license and Iran may be doing so without a license. Iran could have sent one or two Kh-35s to North Korea as the two countries have long exchanged missile tech, via air freight in the knowledge that North Korea had the resources to build its own unauthorized copies. Myanmar (Burma) is also known to share such information with North Korea. The few Kh-35 clones seen in action could be using 1970s technology to do what they obviously did. These missiles use a simple jet engine and travel at up to 700 kilometers an hour. They can use inertial guidance or GPS and be programmed to change course. Terminal guidance can be as primitive as a 1960s era radar homing system or a more modern heat seeking system. Kumsong-3 tests indicate that the North Korean missile had an improved heat seeking terminal-guidance system. Kumsong-3 did have the longer range of the late model Kh-35.
The Kh-35 is similar to the American Harpoon, but is lighter than the 691 kg (1,600 pound) Harpoon and has similar range, which is 224 kilometers for the latest Harpoon version. The Harpoon entered service in 1977 and became one of the most widely used (and emulated) anti-ship missiles in the world, mainly because of reliability and constant upgrades. A 2015 Russian upgrade for the Kh-35 extended range to 260 kilometers and improved the guidance system by adding two-way communications for course changes and improved terminal homing.
The 2017 Kumsong-3 test was given considerable media exposure by the North Koreans. They knew that these tests are closely watched by the U.S., Japan and South Korea. North Korea wanted everyone to think that they had something similar to the latest (2015) version of the Kh-35. But it was also possible that all they had done was extend the range (a simple mod) and used an older terminal guidance system. North Korea had a small target ship out at sea, equipped with a radar enhancement device, which made the ship look larger, as if to imply an American destroyer or carrier. The North Korean target was not moving and had no countermeasures. In combat Western warships, which have lots of experience with missiles like this, have countermeasures and use them regularly in training.