In October 1951, now deployed on the Imjin River as part of 28th British Commonwealth Infantry Brigade, the New Zealand gunners took part in Operation Commando, during which Commonwealth troops advanced from five to seven kilometres through rugged terrain to seize a better defensive line. This was the regiment's busiest month of the war - it fired 72,000 shells.
During November 1951, Chinese counter-attacks sustained the intensity of operations, and the Commonwealth troops were pushed back some distance. In responding to a major Chinese attack on the 4th, the New Zealand regiment fired its highest daily total of the war (10,000 shells). During this phase of the war a great improvement in the Chinese forces' artillery capacity made itself felt.
The Commonwealth Division
These operations were carried out by the 1st Commonwealth Division, which had been formed on 28 July 1951 by combining 29th British Brigade, 28th British Commonwealth Brigade, and 25th Canadian Brigade. New Zealand had welcomed this development - a unique experiment in Commonwealth relations. It agreed to provide a substantial proportion of the divisional signallers, as well as a transport company, as part of an expansion of Kayforce to a strength of 1500 men.
The Expansion Draft left Wellington on the Wahine on 2 August 1951, but was shipwrecked at Masela Island north of Darwin. The men were eventually flown from Darwin to Japan, where Kayforce's base had been established at Hiro in June 1951.
On 15 October 1951 10th Company RNZASC joined the Commonwealth Division, which was commanded by a British general. The non-operational control and general administration of Commonwealth forces in Korea was the responsibility of the Commander-in-Chief, British Commonwealth Forces in Korea, an Australian officer, initially Lieutenant-General Sir Horace Robertson, who was also Commander-in-Chief, British Commonwealth Occupation Force Japan.