Although they bear a striking resemblance to Soviet Kola-class frigates, they are unrelated to any Russian or Chinese design.

[2] The class was originally fitted with a trainable triple 21-inch (533 mm) torpedo launcher, which was replaced in the mid-1980s with fixed P-15 Termit missile launchers taken from Osa-class missile boats.

The design is inherently dangerous, and even a minor missile failure would result in significant damage to the ship.

[2] In 2023, two or more of these frigates remain active with North Korea's navy a full half-century after they were commissioned.

Refitted at Namp'o, the outdated anti-ship missiles, aft 57-millimetre (2.2 in) dual cannon, Drum Tilt fire-control radar and surface search radar were removed, and several new systems were installed.