Chinese naval fleets recently conducted patrols on the South China Sea, reaching as far as Zengmu Reef, the southernmost part of Chinese territory. In an oath-taking ceremony on board Tuesday, the troops and officials vowed to safeguard China's sovereignty.

Earlier this month, a Chinese vessel fired two warning signal shells into the sky to prevent illegal fishing operations by Vietnamese fishermen. Both showed China's firm determination to insist upon its stance amid the South China Sea disputes.

Washington expressed its concerns in both cases, reinforcing its attitude that the US can interfere in the South China Sea issue any time.

Despite the fact that John Kerry, the new US secretary of state, has stepped into office and some side effects brought by his predecessor's aggressive approach are in decline, the US stance on the South China Sea will not fundamentally change. Behind China's frictions with the Philippines and Vietnam is actually the rivalry between Beijing and Washington over the South China Sea.

After Hillary Clinton's four-year intervention into the South China Sea issue with her "smart power" diplomacy, and Manila and Hanoi's frictions with Beijing, all kinds of risks within the South China Sea issue have become evident. All parties involved now have a clearer understanding of each other's national strength and determination.

China, through powerful countermeasures against Manila and Hanoi's provocations, has changed its passive status. Beijing had been worried that frictions on the South China Sea would cause deterioration in its surrounding environment and thus undermine its period of strategic opportunities. Now most of its concerns have been dispelled.

Crises like the Huangyan Island standoff have made one thing explicit - those were, after all, conflicts between countries whose strength were unequally matched. Manila and Hanoi would not have any chance of victory if the South China Sea issue escalated into a confrontation of national strength.

China has no plan to wage a war and recover all the islands illegally occupied by the Philippines and Vietnam. However, China has become more resolute in terms of strikes against the two's provocations.

China's growing leverage over the South China Sea issue stems from stable domestic development. Meanwhile, Manila and Hanoi are witnessing a reduced ability to provoke Beijing over those disputes. Washington is also seeing an increasing number of restraints in its South China Sea policy. The Philippines and Vietnam would face more troubles if they choose to seek fierce confrontation with China.

China should focus on peaceful development. But meanwhile, it is not afraid of adopting resolute measures to protect core national interests. China should avoid external misjudgments toward it, which is pivotal to the nation's long-term strategic environment.