North Korea’s most crucial ally is exploring shifts in its policy toward the authoritarian regime, experts on East Asian relations said last week.

China hasn’t taken any major actions against North Korea beyond signing the U.N. resolution condemning Pyongyang’s May 25 nuclear test and calling for unforced inspections of suspected weapons cargo.

But criticism in China’s government-authorized media of North Korea has grown to levels that were never tolerated until now, said Jonathan Pollack, professor of Asian-Pacific studies at the Naval War College in Newport, R.I. Pollack has written more than 25 books and research reports, including books on U.S.-Chinese relations and on North Korea. His current research centers on North Korean nuclearization.

"What I am seeing is an openness to explore issues. There is much more sanction in authorized media to talk about North Korea in a frank way," Pollack said. "This can be used as a basis for what we have to assume is an internal reassessment, in light of all that is happening now."

In 2003, a Chinese journal published a paper hostile to the Kim regime and was quickly shut down, Pollack said.

Now, a series of articles in World Knowledge, a Chinese Foreign Ministry-backed journal, openly explores what China gets in return for its diplomatic and economic support of Pyongyang.

Other media outlets are discussing the succession of Kim Jong-il, who is rumored to be ill.

"It’s unimaginable that the issue of succession would have been raised in authorized Chinese publications in the past," Pollack said.

"It really suggests to me that they are looking at North Korea differently. It’s definitely a change from the past, in my view."

North Korea’s first nuclear test in 2006 angered China, which feared the test would lead to further militarization of the Asia-Pacific region. But the criticism China allowed at the time was less strident and prevalent than it is now, Pollack said.

China has protected North Korea since hundreds of thousands of Chinese "volunteer" soldiers swarmed past the Yalu River in the early 1950s to force the eventual Korean War armistice. Several South Korean observers said China will continue to support North Korea because it fears a refugee crisis should the current regime destabilize.

China’s economic interests also play a role. China exported more than $2 billion in goods to North Korea last year and received $750 million in imports, according to the Seoul-based Korea Trade-Investment Promotion Agency.

Park Tae-woo, professor of international politics at Taiwan International University, believes the Chinese government is puzzled over its next step toward North Korea. "This is absolutely a turning point for China in finding better ways to handle and tame North Korea," Park said.

Park also said that until now, China has scolded North Korea just enough to protect China’s growing international profile, without destabilizing the Kim regime.

However, a nuclear North Korea gives ammunition to Japanese nationalists calling for a full-scale military to replace its self-defense forces.

It also supports arguments for increased U.S. involvement and training with other regional militaries, which could create a heavily unbalanced strategic alliance against China.

That’s why China will work to tame North Korea’s nuclear ambitions, while the bigger picture demands that Beijing back the Pyongyang regime, said Lee Han-hee, senior fellow for North Korea and East Asia Studies at the Samsung Economic Research Institute in Seoul.

A non-nuclear but still militarily powerful North Korea continues to bolster Chinese influence in the region, while providing a buffer against Western influence on their borders.

"China does not want to lose this great cushion at such a critical time, when it is being reborn as the next world leader," Lee said.