412 Incident was a large-scale purge to Communists in the Chinese Nationalist Party in Shanghai, which was ordered by Chiang Kai-shek, occured on 12 April 1927 during the Northern Expedition. In Chinese, the incident is called Purge to Communists in the party (清黨) by Kuomintang, while the Communist Party of China calls it 412 anti-revolutionary coup(四一二反革命政变) or 412 tragedy(四一二慘案). In the incident, many Communists were prisonized or executed. On the other hand, soon after the incident, an important leader of the Chinese Communist Party, Li Dazhao, who was active in Beijing and the surrounding area, was arrested and executed by Zhang Zuolin, the head of the Beiyang government for matching up the anti-Communist movements led by Chiang. The Chinese Nationalist Party (Traditional Chinese: 中國國民黨; Simplified Chinese: 中国国民党; Hanyu Pinyin: ; Wade-Giles: Chung-kuo Kuo-min-tang; Tongyong Pinyin: Jhōngguó GuómíndÇŽng), commonly known as the Kuomintang (KMT), is a conservative political party currently active in the Republic of China (ROC) on Taiwan. ... Shanghai (Chinese: 上海; pinyin: ; Shanghainese: ), situated on the banks of the Yangtze River Delta in East China, is Chinas largest city by population. ... Chiang Kai-shek (October 31, 1887–April 5, 1975) was a Chinese military and political leader who assumed the leadership of the Kuomintang (KMT) after the 1925 death of Sun Yat-sen. ... April 12 is the 102nd day of the year in the Gregorian calendar (103rd in leap years). ... 1927 (MCMXXVII) was a common year starting on Saturday (link will take you to calendar). ... The Northern Expedition (北伐) was a military campaign led by the Kuomintang (Chinese Nationalist Party) and the Communist Party of China from 1926 to 1927. ... The Chinese Nationalist Party (Traditional Chinese: 中國國民黨; Simplified Chinese: 中国国民党; Hanyu Pinyin: ; Wade-Giles: Chung-kuo Kuo-min-tang; Tongyong Pinyin: Jhōngguó GuómíndÇŽng), commonly known as the Kuomintang (KMT), is a conservative political party currently active in the Republic of China (ROC) on Taiwan. ... The Communist Party of China (CPC) (official name) also known as Chinese Communist Party (CCP) (Simplified Chinese: 中国共产党; Traditional Chinese: 中國共産黨; Pinyin: Zhōngguó GòngchÇŽndÇŽng) is the ruling political party of the Peoples Republic of China. ... Li Dazhao (李大釗, Wades-Giles: Li Ta-chao) (October 29, 1888 - April 28, 1927) was a Chinese intellectual who cofounded the Communist Party of China with Chen Duxiu in 1921. ... Beijing (Chinese: ; pinyin: BÄ›ijÄ«ng; ; IPA: ), a city in northern China (formerly spelled in English as Peking or Peiking), is the capital of the Peoples Republic of China (PRC). ... Chang Tso-Lin (WG) (Chinese: 張作霖, pinyin: Zhāng Zuòlín) (1873 – June 4, 1928), nicknamed the Old Marshall or Mukden Tiger, was a Chinese warlord in Manchuria in the early 20th century. ... After the death of Yuan Shikai,the warlords of Beiyang Army took control of Republic of China. ...

Background

The root of the incident should be the First Cooperation between Kuomintang and the Communist Party of China. In 1923, Dr. Sun Yat-sen, the founder of the Republic of China, said that the Soviet Union had been the most reliable supporter of the revolution career of China and suggested the policy of uniting Kuomintang with the Chiese Communist Party. Soon after that, Sun set the Kumintang government in Guangzhou, and with the help of Third International and Li Dazhao, Chen Duxiu of the Chinese Communist Party, Sun established the Whampoa Military Academy and reorganized Kuomintang with admitting personal participation to Kuomintang of the personnels of the Communist Party. Some of them even became important personnels of Kuomintang, such as Mao Zedong and Zhou Enlai, who served the party as the Minister of promtion and the Vice-manager of politics in the Whampoa Military Acedemy respectively. The First United Front of the Kuomintang, Nationalist Party of China was formed in 1926 to enable the implementation of the Northern Expedition. ... 1923 (MCMXXIII) was a common year starting on Monday (link will take you to calendar). ... Sun Yat-sen (November 12, 1866–March 12, 1925) was a Chinese revolutionary and political leader who had a significant role in the overthrow of the Qing Dynasty. ... Motto: None Anthem: National Anthem of the Republic of China Capital Taipei City (de facto) Nanjing (de jure)1 Largest city Taipei City Official language(s) Mandarin (GuóyÇ”) Government Semi-presidential system  - President Chen Shui-bian  - Vice President Annette Lu  - Premier Su Tseng-chang Establishment Xinhai Revolution   - Declared October... (Simplified Chinese: 广州; Traditional Chinese: 廣州; pinyin: GuÇŽngzhōu; Wade-Giles: Kuang-chou; Postal System Pinyin: Canton) is the capital of Guangdong Province in southern China. ... The term Third International has two well-established meanings: For the unabridged dictionary, see Websters Third New International Dictionary. ... Li Dazhao (李大釗, Wades-Giles: Li Ta-chao) (October 29, 1888 - April 28, 1927) was a Chinese intellectual who cofounded the Communist Party of China with Chen Duxiu in 1921. ... Chen Duxiu (October 8, 1879 – May 27, 1942) played many different roles in Chinese history. ... The Nationalist Party of China Army Officer Academy (Chinese: 中國國民黨陸軍軍官學校; pinyin: ), commonly known as the Whampoa Military Academy (Chinese: 黃埔軍校; pinyin: ), was a military academy in China that produced many prestigious commanders who fought in the Sino-Japanese War and Chinese Civil War. ... This article does not cite its references or sources. ... This is a Chinese name, Zhou is the surname. ...

After the death of Dr. Sun Yat-sen, the political and military leaders were Wang Jingwei and Chiang Kai-shek respectively. Chiang, as a right-wing political figure, started to eliminate the Communists made use of his military power. In July, 1926, Chiang launched the North Expedition at Guangzhou, which restored and controlled the area around the Yangtze River by December. On 9 December, the Kuomintang governement was moved to Wuhan. Wang Jingwei * Courtesy name: Jixin (季新) * Alternate name: Zhaoming (兆銘). Wang Jingwei (Traditional Chinese: 汪精衛; Simplified Chinese: 汪精卫; Hanyu Pinyin: ; Wade-Giles: Wang Ching-wei) (May 4, 1883 – November 10, 1944), was a Chinese politician. ... Chiang Kai-shek (October 31, 1887–April 5, 1975) was a Chinese military and political leader who assumed the leadership of the Kuomintang (KMT) after the 1925 death of Sun Yat-sen. ... Look up July in Wiktionary, the free dictionary. ... 1926 (MCMXXVI) was a common year starting on Friday (link will take you to calendar). ... (Simplified Chinese: 广州; Traditional Chinese: 廣州; pinyin: Guǎngzhōu; Wade-Giles: Kuang-chou; Postal System Pinyin: Canton) is the capital of Guangdong Province in southern China. ... Afternoon light on the jagged grey mountains rising from the Yangtze River gorge The Yangtze River or Chang Jiang is the longest river in Asia and the third longest in the world after the Nile in Africa and the Amazon in South America. ... Look up December in Wiktionary, the free dictionary. ... December 9 is the 343rd day (344th in leap years) of the year in the Gregorian calendar. ... The Chinese Nationalist Party (Traditional Chinese: 中國國民黨; Simplified Chinese: 中国国民党; Hanyu Pinyin: ; Wade-Giles: Chung-kuo Kuo-min-tang; Tongyong Pinyin: Jhōngguó Guómíndǎng), commonly known as the Kuomintang (KMT), is a conservative political party currently active in the Republic of China (ROC) on Taiwan. ... Location within China Modern and ancient Wuhan (Simplified Chinese: 武汉; Traditional Chinese: 武漢; Pinyin: Wǔhàn) is the capital of Hubei province, and is the most populous city in central China. ...

In 3 March 1927, the Shanghaiese workers led by Zhou Enlai launched the third armed uprising, the jointed army between the Zhili clique and Shandong-based army was defeated, occupied the urban Shanghai apart from the international and French settlements. Zhou Enlai established a worker team of 2700 people, waiting for Bai Chongxi, director of the Nationalist army of the Eastern Front to enter Shanghai. 蔣介石等國民黨右派認為共產黨人在國民黨內部勢力日益膨脹，「黨中有黨」，如不早日剪除今後會更難控制。再加上共產黨人在北伐軍攻克的地方搞「打土豪、分田地」的政策被大量國民黨右派所反對，於是蔣介石準備發動政變，暴力清黨。各國租界在蔣保證不以武力改變租界現狀後答應提供援助。 March 3 is the 62nd day of the year in the Gregorian Calendar (63rd in leap years). ... 1927 (MCMXXVII) was a common year starting on Saturday (link will take you to calendar). ... Shanghai (Chinese: 上海; pinyin: ; Shanghainese: ), situated on the banks of the Yangtze River Delta in East China, is Chinas largest city by population. ... This is a Chinese name, Zhou is the surname. ... The Zhili clique (Chinese: ; pinyin: Zhí Xì) was one of several mutually hostile cliques or factions that split from the Beiyang clique during the Republic of Chinas warlord era. ... Shandong (Simplified Chinese: 山东; Traditional Chinese: 山東; Hanyu Pinyin: ; Wade-Giles: Shan-tung) is a coastal province of eastern Peoples Republic of China. ... Pai Chung-hsi (Chinese: 白崇禧, pinyin: Bái Chóngxǐ) (March 18, 1893 - December 1, 1966) was a general of the Republic of China (ROC) and former warlord. ...

The incident

1927年4月2日，蔣介石約李宗仁、白崇禧、黃紹竑、李濟深、張靜江、吳稚暉、李石曾等人，在上海召集中國國民黨中央監察委員會會議，會議中提出檢舉「共產黨連結容納於國民黨之共產黨員，同有謀叛證據」，廣州政治分會主席李濟深首先發言贊同。會議訂立「清黨原則」及組「清黨委員會」，進行反共清黨準備工作。

4月6日，蔣介石派軍樂隊把親題「共同奮鬥」的錦旗，送給上海總工會工人糾察隊，以起到麻痹作用。與此同時，蔣介石指使青幫、洪門頭目黃金榮、張嘯林、杜月笙等出面，組織右派團體「中華共進會」和「上海工界聯合會」，以對抗上海總工會。

4月9日，蔣介石命令成立「淞滬戒嚴司令部」，由白崇禧、周鳳歧分任正副司令，並頒發「戰時戒嚴條例」12條。同日，中央監察委員鄧澤如、吳稚輝、黃紹竑、張靜江、陳果夫等聯名發表《護黨救國通電》(即「青電」)，指責武漢國民政府的「容共」政策。4月11日，蔣介石密令各省「一致實行清黨」。

4月12日凌晨，受蔣介石指揮的「中華共進會」和「上海工界聯合會」幫派分子從上海租界衝出，向上海總工會糾察隊的駐地閘北、南市、浦東、吳淞等處，發起攻擊。之後蔣介石下令淞滬戒嚴司令部所屬國民革命軍第26軍藉口「工人內訌」對工人糾察隊強行繳械，殺傷300多人。

4月13日，上海總工會召開工人大會，聲討蔣介石。會後，10萬多工人、學生到寶山路國民黨26軍第二師周風歧司令部請願。士兵向人群掃射，當場打死100多人，傷者不計其數，釀成大血案。接著，蔣介石下令解散上海特別市臨時政府、上海總工會，和一切共產黨組織，搜捕共產黨員及支持者，逮捕千餘人，並將首要份子槍決。至15日，有300多人被殺，500多人被捕，5000多人失蹤。著名共產黨人汪壽華、陳延年、趙世炎等遇害。

之後其他地方也開始清黨。4月14日，李濟深主持廣州陸海空將領開會議決「清共」，第二天，廣州全城大搜捕。在廈門、福州、寧波、南京、杭州、長沙（馬日事變）等地，一大批共產黨員也遭殺害。共產黨稱之為「白色恐怖」。在北京，張作霖趁機於4月28日殺害了李大釗等20名共產黨人。

事變之後中共和國民黨左派在武漢聯合發動了討蔣運動。4月20日，中共中央發表宣言：「蔣介石業已變為國民革命公開的敵人」，號召人民群眾為「推翻新軍閥」、「打倒軍事專政」而奮鬥。4月22日，宋慶齡、鄧演達、何香凝、譚平山、吳玉章、林祖涵、毛澤東等39人，以國民黨中央執監委員、候補執監委員名義聯名通電討蔣，號召全國民眾及革命同志，起來推翻蔣介石這個「總理之叛徒、本黨之敗類，民眾之蟊賊」。

Aftermath and Significance

4月18日，蔣介石在南京成立了國民政府，和容共的武漢汪精衛政府對立，是為「寧漢分裂」。之後武漢方面也由於事態的發展而在7月15日開始清黨，國民黨與共產黨的合作在7月中旬開始全面破裂。蔣介石通過此事成為了被國民黨內反共的多數派支持，成了最高領袖。雖然不久由於北伐軍在徐州失利而下野，但很快重掌大權，完成北伐，開始了在中國數十年的統治。

四·一二事件使共產黨的發展嚴重受挫。共產黨認為，這標志著「大革命」（即第一次國共合作）的失敗。國民黨主流右派則認為共產黨破壞北伐，清黨使掃除軍閥統一全國的事業得以繼續進行並最終成功。四·一二事件之後，共產黨內主張和國民黨合作的陳獨秀等人受到排擠，甚至被認為是造成共產黨對蔣介石的暴力清黨毫無準備的原因。數月後共產黨聯合國民黨左派在南昌發動八一南昌起義（又稱「南昌暴動」），開始了組建自己的軍隊，進而武裝割據，直到掌握在中國大陸的政權。

幫助蔣介石發動四一二事件的杜月笙則事業順利發展。中國抗日戰爭結束後一度持此功謀求上海市長一職未遂。1949年在國共內戰中，國民政府失敗退往台灣之際，杜月笙害怕自己當年參與四一二事件的經歷令共產黨不會放過他，便逃到香港。