Notes from Wikipedia:
In January 1942 the HK-Kowloon brigade (港九大隊) was established from the Guangdong People's anti-Japanese Guerilla force. In February 1942 with local residents Cai Guo-liang (蔡國梁) as commander and Chen Da-ming (陳達明) as political commissar, they were armed with 30 machine guns and several hundred rifles left by defeated British forces. They numbered about 400 between 1942 and 1945 and operated in Sai Kung. Additionally, the guerillas were noteworthy in rescuing prisoners-of-war, notably Sir Lindsay Ride, Sir Douglas Clague, Professor Gordan King, and David Bosanquet. In December 1943 the Guangdong force reformed the East river guerillas, absorbing the HK-Kowloon brigade into the larger unit.