Portugal Supported by: Republic of China Pro-Beijing organisations(Committee of Thirteen) Supported by: People's Republic of China José Manuel Nobre de Carvalho Ho Yin The 12-3 incident (Chinese: 一二·三事件; Portuguese: Motim 1-2-3) was a series of political demonstrations and riots against Portuguese colonial rule in Macau which occurred on December 3, 1966.

[8] In September 1945, the Republic of China's (ROC) Ministry of Foreign Affairs expressed to the Portuguese government its desire to hand over Macau back to Chinese control.

[13] On November 15, 1966, Urban Services Officers on Taipa blocked further construction of the school, leading to a confrontation between Chinese protesters and Macau Police.

[14] In response, a group of around 60 Chinese students and workers demonstrated outside the Governor's Palace in support of the residents of Taipa Island.

Unlike in neighboring Hong Kong – which faced similar leftist riots – the business community largely did not back the colonial government.

[8] The colonial government subsequently ordered the rioters and demonstrators to be arrested, leading to even more mass discontent and popular support for opposition to the Portuguese administration.

[18] Consequently, martial law was declared, authorizing a Portuguese military garrison and police to crack down on the protests.

[8]: 212–213  The pro-Beijing community in Macau adopted a "Three No's" approach as a means to continue their struggle with the Government: no taxes, no service, and no selling to the Portuguese.

[8]: 211 Negotiations to resolve and prevent further escalation between the PRC, Committee of Thirteen, and the Portuguese government took place in Guangdong.

[26]: 235 With the Portuguese now only nominally in control of Macau, political power would increasingly rest with the pro-Beijing trade unions and business leaders.

[22][30] Emboldened by their success against the Portuguese, the Committee of Thirteen encouraged demonstrations against other institutions in Macau that were perceived to be antagonistic towards the PRC.

Specifically, the British Consulate and the Macau Branch of the Hong Kong Immigration department were once again targeted by protesters.

[32][33] On April 25, 1974, a group of left-wing officers organized a coup d'état in Portugal, overthrowing the ruling right-wing government that had been in power for 48 years.

[24] The Chinese government rejected this proposal, believing that an early handover of Macau would impact relations with Hong Kong.