China is one of six countries with nuclear-powered ballistic missile submarines. Submarine warfare is regarded as a vital part of a country's defense capability.

Wei Daobin, commissar from a submarine base, explains the submarine's structure.

"This is 'the bridge of the submarine'. It is where the naval commander stands and controls the submarine. The two fins on either side raise and lower the submarine," said Wei.

Apart from the structure, Wei also explains how the submarine works under water. "This is the platform for launching the missiles out of the water, similar to normal rockets."

He says China completed a trial launch of a carrier rocket from a ballistic missile-carrying nuclear-powered submarine in 1988.

The test provided solid evidence of the functionality of the domestically produced submarine, which has made China the fifth country capable of launching rockets from nuclear submarines, after the U.S., then Soviet Union, Britain and France.

The nuclear submarine looks big, but the living space inside is pretty small. Therefore, it is vital to make best use of the space to meet the living needs of hundreds of submariners.

"This room can be used for many things, it can be a meeting room, a dining room and also for surgical operations," said Wei.

As submariners shoulder the arduous task of marine training day in and day out, they use a special clock, which does not tell whether it is day or night.

(CNTV.cn October 28, 2013)