What’s going on in murky North Korea? I’ll bet even the US National Security Agency doesn’t know.

The world was shocked last week to learn that North Korea’s boyish dynastic leader, Kim Jong-un, has ordered the public arrest, then swift execution of his uncle by marriage, Jang Song-thaek. Jang was viewed as the North’s second most powerful person.

With usual gentle understatement, North Korea’s news agency called Jang a “despicable human scum.” His crime, it seems, was “trying to cover the sun (i.e. Kim Jong-un) with his hands.” Meaning angering the young sun king.

North Koreans must be very confused. Wasn’t the glorious Kim dynasty, which supposedly descended from the sun, sacred? How could a senior member be a “scum” and merit execution? A religious outrage.

Jang’s very public arrest and execution strongly suggested a grave power struggle in Pyongyang. Shooting your aunt’s husband, no matter how irksome he was, is a big no-no in traditional Buddhist culture, even in bizarre North Korea. It may have been more a sign of young Kim’s weakness than power. American Raj: America ... Eric Margolis Best Price: $9.95 (as of 06:15 EST - Details)

As a long-time Korea watcher, I’m being asked to try to decipher the mysterious business in Pyongyang.

Jang was most likely plotting to oust the erratic young Kim with help from senior army officers. But that was only part of the story.

Behind Jang, I surmise, was big brother China. Jang was well known to be close to Beijing. He was a proponent of North Korea following China’s wildly successful capitalist economic reforms begun by its late great leader, Deng Xiaoping. But such reforms would run directly counter to the Juche (total self reliance) philosophy of North Korea’s founder and Kim’s god-like grandfather, Kim Il-sung.

China has clearly run out of patience with Kim Jong-un even though Beijing supplies all of the North’s oil and much of its food and arms.

The normally discreet Chinese regime has launched scathing criticism of close ally North Korea for its nuclear and missile tests and armed provocations of South Korea, an increasingly important trade and technology partner of China.

Beijing is very angry that Kim’s sabre rattling and immature bombast have allowed Japan, China’s bête noire, to begin building offensive forces just as the two nations are at daggers drawn over the Senkaku/Diaoyu Islands in the East China Sea.

China just made a foolish blunder by creating a so-called air defense zone over the disputed islands (Japan has one there, too). Challenging China, the US promptly flew two unarmed B-52 bombers through China’s new ADZ. All Beijing did was fume and lose face while the Japanese had a big laugh. War at the Top of the ... Eric Margolis Best Price: $1.99 Buy New $14.48 (as of 09:57 EST - Details)

North Korea’s warlike noises – even a threat to nuke the United States – were just hot air, but they gave the US a perfect excuse to move new air and naval units into or around the Korean Peninsula, which is very close to China’s important naval bases at Dalian and Lushun (former Russian Port Arthur), the back door to Beijing.

Pyongyang even attacked the withered Jang for “womanizing” and, far more important, for creating an economic catastrophe. This was a rare open admission that the North again faces economic melt down, even mass starvation.

North Korea’s descent into economic ruin is of enormous concern to Beijing and Seoul. A collapse of the Kim regime would lead to chaos and bloodshed across the north. South Korea dreads this event as “unanticipated reunification:” 25 million starving North Koreans pouring south. South Korea cannot afford to feed and rebuild North Korea as West Germany did with East Germany.

China worries the collapse of the North would lead to South Korea taking it over militarily. And that, to Beijing, means US bases in the North, next to Manchuria’s industrial heartland.

Japan would be no happier with Korean unification: a united Korea would one day be an even more serious trade competitor to Japan and, perhaps, even a military threat.

Beijing was happy with the Korean status quo until the unruly young Kim took power. China usually avoids interfering in its neighbors. But run out of patience, Beijing was probably behind a coup attempt led by Jang, or at least blessed it.

Kim Jong-un will now have to fend off the US, South Korea and China – a tall order even for a sun god.

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