North Korea has crossed the Northern Limit Line 135 times since 2001, a figure fueling controversy over President Roh Moo-hyun's remarks that considering the NLL a border between North and South Korea is a misunderstanding.

◆ North Korea Crosses the NLL 20 Times a Year

According to a report documenting failed attempts to build trust between the two Koreas, North Korean patrol ships have crossed the NLL 65 times and fishing boats 37 times since 2001. The documents were presented by the Defense Ministry to Grand National Party lawmaker Jin Young, a member of the National Assembly's Unification, Foreign Affairs and Trade Committee.

The North crossed the NLL 20 times in 2001, 19 times in 2002, 21 times in 2003, 19 times in 2004, 14 times in 2005 and 21 times in 2006. As of September this year, North Korea had violated the NLL 21 times, the most since 2001 -- six incursions by patrol ships and five by fishing boats. South Korean sailors tackled sea border violations using armed force and firing warning shots until 2004. But since 2005, South Korea has driven North Korean border violators out by giving verbal warnings.

◆ Nonstop Violations

North Korea raised no specific objection to the NLL for 20 years after general Mark Clark, the commander of the UN Command, drew it in late August 1953. But since 1973, the North has kept intentionally crossing it, provoking armed clashes between the two Koreas in the West Sea. In 1973 alone, North Korea violated the NLL 43 times.

Baek Seung-joo, chief researcher of the North Korean Studies Division for the Korean Institute for Defense Analysis, said that the crossing of North Korean fishing boats "can be understood as the pursuit of economic purposes. But patrol ships' violations are an obvious sign that North Korea has no intention to respect the NLL." Baek recalled that the North has repeatedly demanded a redrawing of the line but mainly uses the matter as a convenient pretext to reject South Korean proposal to build up mutual military trust.

It could probably find a new pretext, such as the presence of U.S. forces in South Korea, in refusing to build up military trust even if the South accepts demands related to the NLL. Pyongyang became increasingly vocal on the NLL issue after Seoul deleted the definition of North Korea as the "main enemy" in its defense white papers, a move the North had repeatedly asked for.

Cheong Wa Dae said South Korea proposed drawing up a "peace map" in the West Sea before launching discussions on the NLL issue and North Korea accepted the suggestion. However, when inter-Korean defense minister talks are held in November, the North is likely to demand that the South settle the NLL problem first.

The implementation of most projects produced by the latest inter-Korean summit requires security guarantees from the North Korean military. And it has refused to give them citing the NLL issue. At the summit, Roh agreed with North Korean leader Kim Jong-il on a wide range of projects -- a joint fishing zone, opening freight railway services between Munsan in the South and Bongdong in the North on the reconnected Gyeongui Railway and joint exploitation of resources in the Han River estuary.