Taipei: Taiwan's indigenous defense submarine (IDS) prototype Hai Kun on Sunday released its first official video documenting its submerged sea trials, showing underwater navigation and the launch of countermeasures. The footage provided by the submarine builder CSBC Corp., Taiwan, covers the vessel's first dive, steering and control system tests, and the raising and lowering of the periscope and antenna masts.

According to Focus Taiwan, it offered a rare look at progress in the submarine's sea acceptance test phase. CSBC said the Hai Kun carried out its first trial for shallow-water dives on Jan. 29 and has since completed four submerged tests. The newly released video compiles images recorded between Jan. 29 and Feb. 6, the company said.

The video also shows the submarine leaving port, diving in the test area, launching decoys, resurfacing, and returning to harbor, demonstrating initial sea trial results.