By Ju-min Park and Ben Blanchard
SEOUL/BEIJING (Reuters) - North Korea sent one of its top military officials as a "special envoy" from its leader Kim Jong-un to Beijing on Wednesday, accompanied by a high-powered delegation in what appeared to be a bid to mend frayed relations with its most important ally.
The delegation led by Choe Ryong-hae, vice chairman of the country's top military body, was the most senior to visit China since Kim's kingmaker uncle Jang Song-thaek made the trip in August 2012.
Ties between Pyongyang and Beijing have been hurt by the North's third nuclear test, carried out in February, and by China agreeing to U.N. sanctions on the North and starting to put a squeeze on North Korean banks.
North Korean state news agency KCNA said China's ambassador to Pyongyang, who is seen as the closest of all foreign envoys to Kim Jong-un, saw the delegation off at the airport.
Choe's first meeting in Beijing was with Wang Jiarui, head of the ruling Chinese Communist Party's International Department, China's Xinhua news agency said, without providing details.
The diplomatic move by North Korea came after Japan reached out to Pyongyang last week by sending a special envoy to Prime Minister Shinzo Abe to hold talks over Japanese citizens abducted by the isolated and impoverished state.
Choe is one of the tight coterie of officials around Kim Jong-un, who has been in power for just over a year after succeeding his father.
He is a long-time political administrator and was surprisingly made a vice marshal in the army last year despite having no military background.
Jang's trip in 2012 had been aimed at securing a visit for Kim to Beijing and to win investment for the North's shattered economy, although it appeared to have failed, according to diplomats. Jang is seen as the most powerful official in North Korea after Kim.
"It is an important visit as he (Choe) is both a high-ranked official and coming as a special envoy of Kim Jong-un, and there have been no high level contacts between the two countries for such a long time," said Jin Canrong, associate dean of the School of International Studies at Renmin University in Beijing.
BEIJING LIKELY TO SEEK RETURN TO NUCLEAR TALKS
Jin, a specialist on China-North Korea relations, said Beijing would once again urge Pyongyang to return to the so-called "Six Party Talks" process, aimed at denuclearization.
The talks included the North, China, the United States, South Korea, Japan and Russia and have been stalled since 2009 when North Korea conducted its second nuclear test.
"The Chinese people have been angered by North Korea's provocations. Certainly one of China's demands will be for North Korea to stop doing this," said Jin.
As well as staging the country's third nuclear test, Kim Jong-un presided over the launch of two long range rockets. These are banned by the United Nations due to concerns Pyongyang is testing technology to use in a long-range nuclear missile.
North Korea is almost entirely reliant on China for imports of fuel and food and since it closed an industrial zone on the border with South Korea, has few other outlets for its exports.
The North has traditionally attempted to play China off against the United States and appeared to be open to the possibility of a deal with Japan that irked both Seoul and Washington when Abe's aide visited Pyongyang last week.
Yoshihide Suga, Abe's cabinet secretary, told a news conference on Wednesday that Japan aimed to resume talks with North Korea as part of attempts to resolve the abduction issue.
"Since we are probing all the possibilities, that is naturally included," Suga said.
Japan and North Korea last held government talks in November 2012, before the North's last long-range missile launch in December and nuclear test in February.
Given the spike in tensions between Beijing and Pyongyang in the wake of the February nuclear test, it appeared Choe's visit was unlikely to produce a meaningful accord.
A visit to Beijing for Kim Jong-un would be a major prize for the young leader.
"Jang Song-thaek came back with nothing from China. Since then not only has North Korea not changed, things have become worse," said Lee Ji-sue, a North Korea expert at Myongji University in Seoul.
(Additional reporting by Kiyoshi Takenaka in TOKYO; Editing by David Chance and Dean Yates)