TETSURO KOSAKA, Nikkei senior staff writer
Kim Jong Un stands on the conning tower of a submarine in this undated photo from North Korea's Korean Central News Agency. © Reuters
TOKYO -- As tensions were rising on the Korean peninsula in August, North Korea suddenly deployed about 50 submarines all at once. The move came as a complete surprise to military officials in the U.S., Japan and South Korea.
This new tactic could escalate the military standoff and could eventually come back to haunt the Pyongyang regime.
North Korea is believed to have a fleet of about 70 submarines and submersible vessels. This includes about 20 1,800-ton Romeo-class submarines, as well as a number of 270-ton Sang-O-class submarines which are used to insert special forces teams into enemy territory. The fleet also includes 110-ton Yugo-class subs and a number of midget submarines, which are small submersible vessels. North Korea's Romeo-class submarines are believed to be based on a Chinese vessel, which is a variant of the Russian Romeo-class submarine.
This means that the North has deployed 70% of its known fleet all at once.
Submarines are difficult to locate and track. Often, they are deployed to detect the sounds of another submarine's propellers. Another way is to spread sound-emitting buoys from patrol planes into suspected hiding places in the hope of catching a returning echo.
Most of North Korea's submarine fleet is aging, and the vessels are relatively loud when cruising. Experts say this makes them much easier to detect. However, it is extremely difficult to track every individual submarine when such a large number are deployed all at once. The South Korean military reported that it was unable to track all of them.
In 2010, a South Korean patrol vessel sank after being struck by a torpedo from a North Korean submarine. Given this history, Seoul worried that Pyongyang could launch another surprise attack this time.
If the situation deteriorates, Japan and the U.S. face the possibility that the North Korean submarines may attack Japanese and U.S. ships.
Huge mobilization
The large submarine deployment by the North is a tactic known as a saturation attack, in which the attacking side mobilizes a huge amount of military force at once to overwhelm its opponent.
