China's uphill battle against corruption has entered a critical stage. It's time to crack the hard nuts.

Whether the war on graft will intensify and be a defining historical event hinges on the resolution to take on tough challenges.

The sweeping campaign came as China determined to free up productivity and invigorate creativity by challenging powerful vested interests.

Invariably, behind these interests are corrupt officials protecting each other. The latest gang of thieves who were exposed were senior executives and former executives of the monopolized oil industry.

Reform is futile without removing of the die-hard corruption. High officials who run interference for their corrupt cronies must not be spared.

Whether the top authorities are resolute enough to escalate the war against these highest and mightiest of figures, the "tigers" of the country's anti-corruption discourse, is the litmus test of willingness to improve ordinary people's daily lives.

It is fair to say that how far reform goes depends on how far corruption is curbed.

Corruption contributed to the demise of the Soviet Union. Chinese leaders are all too aware that corruption, if uncurbed, could lead to the fall of the republic and the Communist Party.

When leaders say "No one is above the law no matter what position he holds," it should be more than lip service.

No one should be immune.

The message was clear when prosecutors investigated over 250 public servants at city levels and eight at provincial or ministerial levels last year.

Among those convicted were former member of the Political Bureau of the Communist Party of China Central Committee, Bo Xilai and former Railways Minister Liu Zhijun.

Another hard nut to crack is the law enforcers and discipline inspectors themselves. A Chinese saying goes: "No matter how sharp the knife, it cannot cut its own handle."

In his report to the annual legislative session on Monday, Chief Justice Zhou Qiang warned judges and discipline officials not to bend the law for their personal ends.

To forge iron, one must be strong. That is why the Central Commission for Discipline Inspection of the Communist Party of China will set up an office in the commission itself to oversee its own discipline inspectors.