Before 2000, when the two Koreas held their first summit, the case in point was a secret visit in 1972 to Pyongyang by Lee Hu-rak, then-chief of South Korea's spy agency, to meet with Kim Il-sung, the late founder of North Korea.

When liberal former President Kim Dae-jung took office in 1998, he was active in seeking engagement with Pyongyang and a summit with Kim Jong-il, the late father of North Korea's current leader Kim Jong-un.

In March 2000, Kim sent lawmaker Park Jie-won, then the cultural minister, as a special envoy for discussion over a meeting with the North Korean envoy Song Ho-gyong, the late vice-chairman of the North's Korea Asia-Pacific Peace Committee.

They secretly met in Shanghai to prepare for a summit. In April of that year, they met again and agreed to hold the first inter-Korean summit, in June.

To fine-tune preparation for the summit, the South dispatched Lim Dong-won, then the South's spy chief, in May 2000 as a special emissary to Pyongyang, where he met with Kim Jong-il and other ranking officials.

At that time, South Korea did not make public the sending of a special envoy. The government publicly announced such a move in April 2002 for the first time when Lim Dong-won, an advisor on unification and security, was sent to the North.

Lim was tasked with finding ways to improve inter-Korean ties, which were chilled by US President George W. Bush's tough North Korea policy.

The two Koreas agreed at that time to hold reunions of families separated by the 1950-53 Korean War, but Lim's visit fell short of bringing rapprochement to the Korean Peninsula.

Bush's designation of North Korea as part of the axis of evil heightened tensions between the North and the US.

Their friction intensified due to the North's suspected development of highly-enriched uranium and its pullout from the Treaty on the Non-Proliferation of Nuclear Weapons in January 2003.

President Kim sent Lim as a special envoy again, but he had to return home without meeting with Kim Jong-il.

Former liberal President Roh Moo-hyun, Kim Dae-jung's successor, sent special emissaries to the North to resolve the nuclear standoff.

A trip by Chung Dong-young, then the unification minister, in June 2005 helped the North return to the six-party denuclearization talks.

Under the Sept. 19 accord, North Korea agreed to dismantle its nuclear program in exchange for a security guarantee and energy.

Chung visited the North for a joint pro-unification event marking the fifth anniversary of the 2000 inter-Korean summit. But he was actually a special envoy seeking to resolve the North's nuclear issue.

Roh also sent Kim Man-bok, then the chief of the South's intelligence agency, in August 2007 to deliver a letter from him to Kim Jong-il ahead of the inter-Korean summit in October of that year. (Yonhap)