vessels have frequently occurred along the NLL. As the waters along the NLL are rich in blue crab, the seaborne clashes have sometimes been dubbed the "Crab Wars". Incidents include: First Battle of Yeonpyeong (1999) – four North Korean patrol boats and a group of fishing boats crossed the border and initiated a gun battle that left one North Korean vessel sunk, five patrol boats damaged, 30 sailors killed, and 70 wounded. Second Battle of Yeonpyeong (2002) – two North Korean patrol boats crossed the NLL near Yeonpyeong island and started firing; after becoming outnumbered and suffering damage, the vessels retreated. On 1 November 2004 three North Korean vessels crossed the NLL. They were challenged by South Korean patrol boats, but did not respond. The ROK vessels opened fire and the DPRK boats withdrew without returning fire. No casualties were reported. Battle of Daecheong (2009) – A North Korean gun boat crossed the NLL and entered waters near Daecheong Island, South Korean vessels opened fire reportedly causing serious damage to a North Korean patrol ship and one death. On January 27, 2010, North Korea fired artillery shots into the water near the NLL and South Korean vessels returned fire. The incident took place near the South Korean-controlled Baengnyeong Island. Three days later, North Korea continued to fire artillery shots towards the area. ROKS Cheonan sinking (2010) – The ROKS Cheonan (PCC-772), a South Korean corvette, was sunk by an explosion, killing 46 sailors; the resulting South-Korea-led international investigation blamed North Korea, which denied involvement. Bombardment of Yeonpyeong (2010) – North Korean forces fired around 170 artillery shells at Yeonpyeong, killing four South Koreans, injuring 19, and causing widespread damage to the island's civilian fishing village. See also Armistice Agreement of 1953 – full text of the armistice Korean Demilitarized Zone - land border Syngman Rhee Line - 1950s South Korean maritime boundary claim beyond accepted territorial waters References Further reading Van Dyke, Jon M., Mark J. Valencia and Jenny Miller Garmendia. "The North/South Korea Boundary Dispute in the Yellow (West) Sea". Marine Policy 27 (2003), 143–158. Roehrig, Terence. "The Origins of the Northern Limit Line Dispute". NKIDP e-Dossier no. 6 (May 2012). Disputed waters Territorial disputes of North Korea Territorial disputes of South Korea Military history of Korea North Korea–South Korea border North Korea–South Korea relations Government of North Korea Military of North Korea Korea-related lists International borders