The riots took their name from the common designation of a patriotic holiday on October 10, the tenth day of the tenth month, marking the anniversary of the establishment of the Chinese Republic in 1911. In Hong Kong, it is preceded by the October 1 celebration of the birthday of Red China. Each holiday gave Nationalist or Communist sympathizers an opportunity to explode strings of firecrackers, hold rallies and fly their national flags. On both days, police were out in full force to prevent riots between the opposing Chinese groups, and they managed to keep the lid down fairly well until 1956. The October 1 holiday in 1956 passed without undue commotion and October 10 began with no indication of Communist violence. Nationalist flags were displayed by refugees all over the colony, particularly in the heavily populated resettlement estates of Upper Kowloon. The refugees were predominantly pro-Nationalist, having been driven from their homeland by the Reds. After years of exile and grinding poverty, many of them were steeped in bitterness and yearning for revenge against the Communists. The Triad gangs, whose members played a key part in the Double Ten riots, had been established in China three centuries ago as a patriotic society dedicated to the overthrow of the foreign Manchus who dethroned the native Ming Dynasty. Their professed ideals slowly rotted away and they devolved into a band of thugs, living on protection rackets, shake-downs of street peddlers and petty criminals, enforced by fear and strong-arm brutality. Since World War I, crime has become their primary business and their patriotism survives only as a front. On October 10, 1956, pro-Nationalist residents of the Shek Kip Mei Resettlement Estate began to take down the paper flags they had pasted on the concrete walls of the housing blocks. Housing officials had objected that the pasted flags were difficult to remove after the Double Ten holiday was over, and the tenants, who could still fly flags from poles or ropes, accepted the cleanup job unprotestingly. At Li Cheng Uk, a resettlement estate about a quarter of a mile to the northwest of Shek Kip Mei, housing officials themselves removed Nationalist flags and symbols stuck on the walls. It was early in the morning of the Double Tenth, when an unfriendly crowd of about 400 gathered quickly and demanded that the flags be restored. Police were called, but the crowd swelled to more than 2,000 by early afternoon and its demands became more extravagant. Impatient for action, some of the crowd attacked two resettlement officials, beating them severely. Police units, hurrying to help the injured men, were met with a barrage of flying bottles. They replied with tear gas and the mob, turning its anger on the police, showered them with rocks. A resettlement office was set afire but police reinforcements succeeded in dispersing the mob. By midafternoon, with two persons arrested and four injured, peace appeared to have been restored.