Area on December 23, 1985. On October 15, 1994, UNC Commander directed that the unit be known by its present designation, the United Nations Command Security Battalion—Joint Security Area. Originally a purely U.S. Army organization, the unit also included ROK soldiers (KATUSAs). In addition, ROK Army officers served as liaison officers. In the mid-1970s the JSA consisted of the JSF company with three platoons of one U.S. and one ROKA officer, and thirty enlisted men, supported by a battalion staff. The three platoons were led by the U.S. officer with the ROK officer as the executive officer, and U.S. Army platoon sergeants. The platoons consisted of three squads, with equal numbers of U.S. and KATUSA soldiers. Sometime after 1979, another (fourth) platoon was added to the JSF to allow time for training during platoon work rotations. In July 1987 the four platoons of the Joint Security Force (JSF) company were reorganized to mix KATUSA and US soldiers at all levels. At the platoon level, two platoons were led by U.S. Army lieutenants and ROKA platoon sergeants, and two were led by ROKA lieutenants and US Army platoon sergeants. In November 1987 the unit received a ROK Army major as its first deputy commander. On April 25, 1992, the JSF company became a KATUSA-pure formation. Captain Yin Sung-hwan became the first ROK commander assisted by a U.S. Army lieutenant as his executive officer. The number of U.S. Army personnel assigned to the unit fell below 200 for the first time since 1952. American forces assigned to the JSA assumed mainly administrative and support roles. On October 31, 2004, a ROK Army battalion assumed sole responsibility for the Joint Security Area. This modified light infantry battalion consisted of a battalion headquarters, a headquarters company, two security companies, and a civil affairs company. The number of U.S. personnel assigned decreased further, reflecting the UNC Commander's desire to minimize the USFK presence near the Korean Demilitarized Zone. The commander of the ROKA JSA Battalion serves as the UNCSB-JSA Deputy Commander. The UNCSB-JSA Commander's principal responsibility now lies in his operational control of selected ROKA formations during both Armistice and wartime periods. Both sides placed guards between the blue meeting houses, where the demarcation line is marked by blocks of concrete. South Korean guards in this area were armed with pistols and they stood in a modified taekwondo stance with stolid facial expressions, clenched fists