TOKYO -- Today marks the fifth anniversary of Japan's nationalization of the Senkaku Islands by buying them from private landowners, a move that triggered massive waves of often violent anti-Japanese protests across China.

The islands, located in the East China Sea, are administered by Japan but claimed by China, which calls them the Diaoyu Islands.

Since the move, Chinese ships have encroached in Japanese waters around the islands on a near daily basis, with intrusions intensifying this year.

Tokyo wants to find a diplomatic solution to the issue while it beefs up the Japan Coast Guard, but there are no signs of tensions easing.

Strong presence

At the end of August, state-run China Central Television aired a video showing a China Coast Guard vessel operating near the islands. In the video, a Chinese crew member is seen radioing a warning message to a JCG patrol boat operating within Japanese waters.

Speaking in Japanese, the seaman informs the JCG boat that it had entered territory under Chinese jurisdiction, urging it to "obey the law."

The video, part of a CCTV program about China's diplomacy, included footage of the CCG ship taken from above by a drone, with the outlines of the Senkakus vaguely visible.

After analyzing the video, which was also uploaded to YouTube, a Japanese official explained that it had apparently been taken when the Chinese ship was in Japan's waters near the Senkakus. The video was probably used to publicize daily CCG operations, the official added.

Broadcast of the video prompted Japan's Foreign Ministry to lodge a protest with China through diplomatic channels.

After the vessel launched the drone, two Japanese Air Self-Defense Force F-15 fighter jets scrambled in response to violation of Japan's airspace.

Since Japan nationalized the Senkakus in September 2012, Chinese government ships have frequently entered territorial waters near the islands and in the adjacent contiguous zone. While the number of these incursions fluctuates monthly, they remain fairly high, except during the winter when seas are rough, according to a JCG official. In June last year, a Chinese military vessel entered the contiguous zone -- the first incident of its kind.

Later in August the same year, a large flotilla of over 200 Chinese fishing boats appeared in the zone while 23 instances of Chinese government ships encroaching on Japanese territory were recorded. This again was a first of what appear to be coordinated actions of Chinese government vessels and fishing boats repeatedly violating Japan's maritime borders.

According to a senior official of the Japanese Foreign Ministry, the choreography is an attempt by Beijing to show that they are properly monitoring Chinese fishing boats in their own territory.

Not going away

Japanese officials talk of a "three, four, two pattern," emerging. Three times a month, four Chinese ships enter Japanese waters for a period of two hours each.

Meanwhile, the CCG has upgraded its military capabilities. It now has two huge ships of around 10,000 tons, each armed with heavy caliber machine guns.

Since nationalization of the Senkakus, the JCG has also beefed up its fleet, increasing the number of ships carrying helicopters and large patrol boats of around 1,000 tons to 19, up from seven. It is also steadily increasing the number of officers by about 100 annually.

In October last year, the JCG set up a special unit dedicated to patrolling the Senkakus, with 14 ships now regularly operating in the area.

The JCG has requested a record 230 billion yen ($2.13 billion) for the fiscal year that started in April. But it will become difficult for it to keep pace with the the rapid expansion of the CCG. Tokyo has predicted that the CCG will have 145 1,000-ton ships in 2019, more than twice as many as the JCG.

Tensions over the Senkakus have also been exacerbated by Chinese violations of Japanese airspace. Last year, Japan's Air Self-Defense Force scrambled 842 times -- a new record -- in response to Chinese military aircraft, up 81% from the previous year.

Japanse Prime Minister Shinzo Abe has made diplomatic overtures to Beijing to ease tensions. When he met with Chinese President Xi Jinping in Hamburg in July, Abe said the East China Sea should become a sea of peace, friendship and cooperation. Xi responded by saying it is important to maintain peace and stability in the East China Sea.

While the two leaders are considering regular mutual visits to each other's country, both have shown their intransigence on the issue of sovereignty.

Eroding control

China's strategy is to slowly chip away at Japan's effective control of the islands. Hardliners within the Communist Party and the army call for military action, but Beijing has been developing the legal infrastructure to support its territorial claim.

During the annual session of the National People's Congress in March last year, a report by the Supreme People's Court referred to a Chinese court mediating the case of a maritime collision that had occurred near the islands. The report argued that the case demonstrated China's jurisdiction over areas surrounding the islands.

China wants to have a fully modernized socialist society by 2049, the 100th anniversary of the communist government's founding. This goal is seen as signaling China's ambition to regain its status as a world power. For this, the country will need a formidable navy, which Xi is now pushing to expand.

But China has no more desire to start a military clash over the islands than Japan. Rather, Beijing is betting that it can gradually erode Japan's control through repeated intrusions by Chinese fishing boats and government vessels -- essentially accumulating enough fait accomplis until its control is complete.

It is a dicey strategy, but clearly Beijing's preferred course of action as it slowly tries to change the status quo.