China is currently commissioning two of the world’s largest coast guard cutters, ships that could alter the balance of power in the South and East China Seas (one ship is to be stationed in both seas).

Known only by their hull numbers, in this case Haijing 2901 and Haijing 3901 (the first digit denotes which sea it is to patrol). They will displace 10,000 tonnes, possibly more when fully outfitted.

That makes them larger than the US Navy’s Ticonderoga-class cruisers and the largest Japanese coast guard cutter, the 6,500-tonne Shikishima were previously the largest cutters in the world. The largest cutter belonging to a Southeast Asian coast guard is Vietnam’s DN2000 class at 2,500 tons

The new ships are not necessarily heavily armed. Pictures that have been published so far show that they lack gun turrets. It is not armaments that make these two coast guard Dreadnaughts so formidable; it is their sheer size.

The People’s Daily, the organ of the Chinese Communist Party, boasted that the powerful new ship could ram and possibly sink a 9,000-ton vessel without damaging itself. That makes then a potential threat to regular naval vessels of the US and Japanese navies.

The USS Forth Worth, a Littoral Combat ship, based in Singapore and which has undertaken Freedom of Navigation Operations in the Spratly islands, displaces a mere 1,200 tons. A warship like the Fort Worth could, of course, defend itself from a Chinese vessel on a collision course, but it would mean firing the first shot.

Ramming has been a tactic in territorial disputes in both the East and South China Seas, harkening back to the days of the Romans and Carthaginians. A large Chinese fishing vessel rammed a Japanese Coast Guard cutter near the Diaoyu/Senkaku islands in 2011.

In the 2014 standoff between Vietnam and China over Beijing’s planting an oil-drilling rig in Vietnam’s Exclusive Economic Zone, the Chinese Coast Guard rammed and fired water cannons at the Vietnamese vessels.

Coast guard vessels are not true warships. Usually, they are armed with machine guns or possibly medium caliber deck guns, if they are armed at all. The Larger Japanese Coast Guard vessels are armed with 40 and 22 mm guns.

But even without firepower, these new coast guard vessels can throw their weight around.

• In April, 2012, Chinese Maritime Enforcement vessels, (later renamed the Chinese Coast Guard), blocked the Philippine Navy from arresting Chinese fishing boats in the Philippine-claimed Scarborough Shoal in northern South China Sea. They have also interfered with the resupply of Philippine Marines on St Thomas Shoal.

• In May, 2014 A dangerous standoff when China moved an oil drilling rig in Tonkin Gulf area of Vietnam’ Exclusive Economic Zone (EEZ). Hanoi says the Chinese Coast Guard sank one of its own coast guard boats

• Malaysia complains that the Chinese Coast Guard has been maintaining a presence near the Malaysia-claimed Luconia Shoals for over a year harassing its fishing boats.

Captain James Fanell, formerly chief of intelligence for the US Pacific Fleet, calls the Chinese Coast Guard a full-time marine harassment organization. Unlike the US Coast Guard, the Chinese service has no other mission but to harass other nations into submitting to China’s extravagant claims,” he says.

Fanell notes that China is building new coast guard vessels, like the two super cutters, at “an astonishing rate.” China used to convert former navy frigates that had been retired into coast guard vessels, but it is now turning out purpose-built cutters.

Chinese Coast Guard vessels intrude on Japanese-claimed territorial waters around the disputed Diaoyu/Senkaku islets on an average of once every two weeks. They linger for an hour or so, challenge their Japan Coast Guard shadows to depart “Chinese territorial waters” then leave.

There is reason to believe that this routine is changing in ominous ways. In November for the first time, one of the coast guard vessels spotted intruding on Senkaku waters was armed with cannon.

In November a formation of 11 Chinese air force long-range bombers and associated support craft flew through the Miyako Channel separating Okinawa from Miyako Island. They flew about 600 miles into the Western Pacific then returned home.

In December four Chinese Coast Guard vessels together entered the Japanese-claimed waters, an unusually large number for such an exercise. One of them was armed with deck guns.

Tokyo is also suspicious about the recent activities of the regular Chinese navy in waters near the disputed islands. A contingent of Chinese frigates now hovers about 70 km away from the islands, close enough to come to the aid of any of its coast guard vessels that gets in trouble.

The Japanese were especially intrigued by movements of one of China’s new Dongdiao-class electronic surveillance ships, which sailed back and forth about 40 km from the Senkaku, the closest that any Chinese naval vessel has come to the islands.

The incidents in November and December prompted the Japanese government to make public what the cabinet had decided earlier in the year, that Japanese naval vessels might intervene should the coast guard be unable for some reason to do its normal “policing” duties.

“If it becomes difficult for the police and the Japan Coast Guard, then the Maritime Self Defense Force (navy) could respond,” said defense minister Gen Nakatani. That would happen if Chinese navy ships actually entered Senkaku waters.

“If a foreign warship enters Japanese territorial waters, and its navigation does not constitute ‘innocent passage,’ Tokyo is ready to mobilize the Maritime Self Defense Force,” said Chief Cabinet Secretary Yoshihide Suga.

The use of “white hulls,” mostly unarmed coast guard cutters, rather than “gray hulls,” has been a stabilizing element in the numerous territorial encounters of the past few year. The recent remarks suggest that Tokyo expects to see more gray hulls than white hulls in the coming year.