FACTBOX: North Korean diplomacy: fog at end of tunnel

SEOUL (Reuters) - China's prime minister will visit North Korea early next week, a trip that could help revive stalled talks on ending Pyongyang's nuclear ambitions.

It is the latest signal the reclusive North is willing to engage with an outside world from which it has been even further ostracized after its second nuclear test in May.

But Pyongyang has a history of quickly shifting tack in its diplomatic and nuclear dealings.

Here are a few incidents over the years:

RECOGNITION AND CONFRONTATION

North and South Korea struck a landmark accord in December 1991 where they pledged for the first time to recognize each other and end military confrontation. This became the agreement that served as the basis for future cooperation and nuclear negotiations. Two months later, North Korea naval vessels sank two South Korean fishing boats and detained about 30 sailors.

A SUMMIT FOR PEACE, AND THEN A BOMB THREAT

Leaders from the two Koreas held their first summit in June 2000. The meeting in Pyongyang of then-South Korean President Kim Dae-jung and North Korean leader Kim Jong-il led to increased cooperation and ushered in a brief era when the reclusive North opened up. The next month, North Korea threatened to blow up a leading South Korean daily for slandering its leaders.

RADIOACTIVE BARGAINING

In August 2003 six-way nuclear talks began among the two Koreas, China, Japan, Russia and the United States that raised hopes a diplomatic solution could be reached to end Pyongyang's atomic ambitions. But North Korea darkened the mood at the discussions by threatening to test a nuclear bomb and fire off a new type of missile. It also agreed to more talks.

CAN YOU SPARE A NUCLEAR REACTOR?

The six-countries reached a landmark deal in September 2005 under which North Korea would in principal scrap its nuclear arms program in exchange for massive aid and an end to its international ostracism. A day after the accord was announced, North Korea said it would only abide by agreement if the United States gave it light-water nuclear reactors first. Washington refused, saying it was not part of the deal.

TOPPLING TOWERS AND TOPPLING DEALS

In June 2008, North Korea made the most symbolic showing of its commitment to a six-country deal by blowing up the cooling tower at its Yongbyon nuclear reactor. Within a month, Pyongyang threatened to scuttle the deal unless the United States removed it from a terrorism blacklist. The deal eventually fell apart in the following months with the North angry about the pace of aid delivery, what it saw as hostile U.S. policies and provisions that would allow foreign inspectors to remove nuclear samples from its territory.

(Reporting by Jon Herskovitz; Editing by Jonathan Thatcher and Sanjeev Miglani)