From South Korea's deployment of the THAAD defense system, to the victory of the Japanese right Upper House election and the Philippines' ignorance of China's sovereignty and national interests, China's eastward security situation is deteriorating. The unclear cross-Straits relationship may also strike a blow to the current peaceful pattern at any time. Therefore, the major challenges and threats China may face in the next 10 to 20 years come from the east. China's eastward security and stability hinge on the development of its sea power.

The traditional threats facing China mainly come from the land, especially from its northwestern borders. The Great Wall, created over many centuries, is a token of China's efforts in land defense. China witnessed a rapid development in the 15th century, when Zheng He's voyages travelled to the eastern coast of Africa. Regrettably, the ban on maritime trade in the Ming Dynasty (1368-1644) has laid bare the shortcomings of China's conservative defense, and eventually resulted in the passive situation where China was challenged from the directions of both sea and land for hundreds of years.

In the 19th century, Western powers invaded China by sea, posing fatal challenges to China's defense strategies that had lasted for thousands of years. Western invasion triggered heated discussions among Chinese officials on the nation's defense system. As a result, the Qing government (1644-1912) shifted its focus from land defense to the sea. However, after the First Sino-Japanese War (1894-95), the Chinese government had no capability to reverse the passive situation any more.

History deserves remembering. After surpassing Japan to become the largest economy in Asia, China is now strong enough to adjust its marine policies. The major maritime threats in the Ming and Qing dynasties came from pirates, and thus the governments lacked a sense of crisis. Disdaining doing businesses with foreign countries, the feudal governments imposed a ban on maritime trade.

However, today's China, which no longer has a tributary system, is facing a totally different situation. The surrounding waters have already been fragmented by interwoven demarcation lines. The major threats that China is facing at present are an increasing number of drills and the presence of warships from different countries.

China is diverting its development focus from its eastern provinces, which are home to nearly 40 percent of the nation's overall population and contribute 57 percent of the GDP. And with a sharp rise in its outbound investments and the number of citizens overseas, China is rapidly expanding its influence outward. The openness of the export market, the stable supplies of energy and resources, the security of shipping lanes and the political development of other countries are increasingly connected to China's interests.

Most traditional threats from the land have been addressed after decades of negotiations. After the settlements of the territorial disputes with other neighboring countries, save for those with India and Bhutan, China is now able to devote more energies to its maritime policies.

Noticeably, while the US and the Philippines are playing with fire on the South China Sea, China and its northern neighbors have strengthened political and economic cooperation in virtue of the Shanghai Cooperation Organization. Facing challenges from the US and its allies, the land is no longer where the prime threat comes from for China. The quasi-alliance between China and Russia serves as an importance basis for China to cope with maritime challenges.

However, China should be cautious with its strategies. It is necessary to guard both of the two lines of defense. Given the geopolitical characteristics of China, some scholars believe China, like France and Turkey, is an example of a hybrid country that borders with both land and sea. Countries of this type find it hard to become a power both in land and sea, but have to face pressure from both directions. This may not be true for China, but should inspire us to greater efforts.

The author is an associate research fellow at the Institute of International Relations, Shanghai Academy of Social Sciences. opinion@globaltimes.com.cn