The capture of Bessang Pass on June 14, 1945, was one of the glorious achievements of the Filipino and American officers and men of the U.S. Army Forces in the Philippines, North Luzon (USAFIP, NL), a force of over 20,000 officers and men under the overall command of Colonel Russell W. Volckmann, a graduate of the U.S. Military Academy and a veteran of the Battle of Bataan.

All the five (5) infantry regiments of the USAFIP, NL - the 121st, 15th, 66th, 11th and 14th - and their supporting engineer, signal, quartermaster, ordinance, and medical units contributed to the victory in Bessang Pass.

It was the 121st Infantry however, which had the most number of troops engaged in the operation. One of its units, the "L" company under the command of Lt. Emilio Narcise, continuously operated around the Bessang Pass area from January to June 14, 1945. After participating in the battle which resulted in the liberation of San Fernando, the capital town of La Union, on March 23, 1945. All the three battalions of the 121st were employed in the operations to capture Bessang Pass. 

The Makeup of United States Army Forces of Northern Luzon (USAFIP-NL), comprised of both American and Filipino soldiers and guerrillas. The organized task force was led and commanded by General Russel W. Volckmann.   USAFIP-NL served as a military force that numbered more than 8000 infantrymen that  hailed from the 11th, 14th, 15th, 66th, and the 121st Infantry Regiments.  The Filipino guerrillas under Volckmann’s  leadership were made up of various Filipino ethnic minorities from the northern cordilleras/mountain passes and ranges.  The northern guerrillas’ knowledge of the mountainous terrain were crucial in helping to eliminate the last stronghold of the Japanese military out of Northern Luzon.

Source:https://pvao.gov.ph/wp-content/uploads/2018/02/Battle-for-Bessang-Pass.pdf