Chinese Premier Wen Jiabao is expected to hold talks with North Korean leader Kim Jong-il on a three-day visit he began on Sunday, when the neighbors signed a pact on China's economic aid to the impoverished North.

Following are some points on how Wen's visit is playing out against the backdrop of international efforts to jump start stalled talks on ending the North's nuclear arms ambitions.

WHAT IS WEN'S MISSION?

China wants nothing more than to put back on track the six-party nuclear talks it has hosted since 2003. If North Korea manages to hold direct talks with the United States, as it is hoping to, and turn it into a forum for bargaining on its nuclear arsenal, China's status as a diplomatic powerhouse negotiating a major conflict will suffer.

But Wen is unlikely to go home empty-handed, especially after offering economic aid to the impoverished neighbor and signing major treaties that affirmed China's role as the single most important lifeline for the North.

His trip is taking place more than four months after the North's second nuclear test in May and after several high-level visits by China to Pyongyang were scrapped in displeasure. It indicates there is now an understanding between the countries that the North will soon announce a return to multilateral dialogue, most likely hosted by Beijing.

WHAT DOES CHINA MEAN TO NORTH KOREA?

China is the closest that the North has to a major ally, and has been steadfast in backing the isolated state through decades of brinkmanship by Pyongyang as it built a nuclear arms program. Beijing has provided food and other aid to the North through famine and dire economic conditions. But Pyongyang has seen in recent months a less patient Beijing after its second nuclear test in May drew U.N. sanctions that China backed. China had been under intense pressure from the United States and South Korea to join in the sanctions.

For China, North Korea has been a buffer from U.S. influence into its mainland through capitalist South Korea. But it worries that a nuclear-armed North Korea could trigger a regional arms race.

WILL NORTH KOREA COMPLETELY GIVE UP ITS NUCLEAR ARSENAL?

North Korea's leaders have said it is the country's ultimate goal to end its nuclear program and remove all atomic arms from the peninsula. But Pyongyang has linked that with the end of Washington's hostile policy against the North and the removal of U.S. military from South Korea.

Some analysts say this will never happen and the North will never give up the only leverage it has in the international community, especially when China stands ready to offer aid and prop up its regime.

Wen's visit reflects the ambivalence that marks China's ties with North Korea. China wants North Korea to stop developing nuclear weapons, but it also fears that excessive pressure on the North could unleash dangerous instability there, possibly sending a flood of refugees into adjacent northeast China.

(Reporting by Jack Kim; Editing by Jonathan Hopfner and Ron Popeski)

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