Ch'ai Ta-chi 柴大紀 (T. 肇修 H. 東山, d. Aug. 1788, general, was a native of Chiang-shan, Chekiang. A military chin-shih of 1763, he was sent to Fukien as an expectant second captain, but had to wait eight years before he obtained appointment to a vacancy. In 1775 he became a major, and two years later was transferred to the Pescadores. In 1778 he was promoted to be a lieutenant-colonel but in the same year was sent to Hunan as a colonel in command of the naval forces on Tungting Lake. In 1781 he was made a brigade-general and was placed in command of the troops on the island of Hai-t'an. Late in 1783 he was transferred to Formosa which was then under the jurisdiction of the province of Fukien. Late in 1785 he was about to be sent back to the mainland when a local uprising of aborigines took place. But he was retained on the island and in 1786 was ordered to remain there as brigade-general.
At this time the Chinese settlers in Formosa, mostly Fukienese, were divided into two main camps — those who came from Ch'üan-chou and those who came from Chang-chou. In 1782 the authorities had executed a Chang-chou gambler and murderer, and thereby antagonized his fellow-townsmen. The Ch'üan-chou men, who opposed the Chang-chou men, lent their support to the authorities. As most of the Chang-chou men were members of the secret society known as T'ien-ti hui 天地會, they used this organization to oppose the local officials. The leader of the society in the northern part of Formosa, Lin Shuang-wên 林爽文 (d. 1788), a resident of Chang-hua, made preparations to rebel when an opportunity came. In 1786 some of the members of the society in Chu-lo were arrested but were soon freed by their armed followers. Ch'ai Ta-chi hastened to the scene and, after executing several ring-leaders, returned to the capital of the island, T'ai-wan-fu (Tainan). But Lin Shuang-wên, angered at the oppression suffered by the society, rallied his followers in Chang-hua and revolted late in December, taking that city on January 16, 1787, and Chu-lo eight days later. Meanwhile Chuang Ta-t'ien 莊大田 (d. 1788), the leader of the society in the southern part of the island, led his men in an attack on T'ai-wan-fu, but was repulsed by Ch'ai who was aided by city-dwellers, chiefly from Ch'üan-chou Fukien, who were hostile to the natives of Changchou. After this setback, Chuang Ta-t'ien was satisfied with the capture, on January 31, 1787, of the city of Fêng-shan. Thus, except for T'ai-wan-fu in the south and Tan-shui (Taipeh) in the extreme north, rebellion was rampant throughout the island and Lin Shuang-wên was proclaimed ruler at Chang-hua with the reign-title, Shun-t'ien 順天.
The provincial forces of Fukien who were detailed to suppress the rebels were now placed under the command of Ch'ang-ch'ing (see under Li Shih-yao) whose post as governor-general of Fukien was entrusted to Li Shih-yao [q.v.]. With the assistance of forces from the mainland, Ch'ai Ta-chi drove northward and recaptured Chu-lo (March 1787). After repulsing rebel attacks for three months he was promoted to the rank of provincial commander-in-chief of the land forces of Fukien, but remained in Formosa as brigade general. Meanwhile the campaign elsewhere on the island came to a stalemate, and the rebels were permitted to consolidate their gains. Early in August Fu-k'ang-an [q.v.] was ordered to replace Ch'ang-ch'ing as commander-in-chief but did not arrive on the island until December 8, 1787. From the preceding September onward Ch'ai and his men had been besieged in the city of Chu-lo. When ordered to abandon the city, Ch'ai replied that he could not endure to leave tens of thousands of civilians to be slaughtered by the rebels. For this stand he was given the hereditary rank of a first class earl with the designation, I-yung (義勇伯). The city of Chu-lo had its name changed to Chia-i 嘉義, "Commendable Loyalty", out of respect to the civilians of that city who assisted in the defense. The siege was raised by Fu-k'ang-an on December 16, 1787. After the capture of Lin Shuangwên on February 10, 1788, and of Chuang Ta-t'ien on March 12, the rebellion came to an end. The rebel leaders were taken to Peking and executed.
As for Ch'ai Ta-chi, he was not only forbidden to take any credit for the campaign but was disgraced and tried. It seems that he did not pay Fu-k'ang-an due respect when the two met at Chu-lo. As soon as Fu-k'ang-an entered that city he reported that Ch'ai was untrustworthy. His henchmen, apparently in co-operation with Ho-shên[q.v.], lodged a number of charges against Ch'ai, among them his alleged mistakes in dealing with the rebels and his alleged corrupt practices. The task of obtaining testimony and evidence against Ch'ai was entrusted, perhaps purposely, to Fu-k'ang-an who also conducted the trial. At the same time men like Li Shih-yao and Ch'ang-ch'ing were urged to bring testimony against Ch'ai. Ch'ai's successful defense of Chu-lo was discredited and was attributed to the bravery  of the civilians. The whole case was clearly a conspiracy, but no one dared to defend the victim. Ch'ai was forced to sign a confession and on this ground he was slated for execution. In August he was delivered to Peking for re-examination, but he refused to admit his "crimes", asserting that his confession was obtained by force. When questioned by the emperor he denounced the injustice done him and even argued with the emperor. For this breach of etiquette he was beheaded on or about August 22, 1788. Later his son was banished to Ili as a slave.
According to Chao-lien [q.v.], the rebellion in Formosa might easily have been suppressed if the command had not been entrusted to Ch'ang-ch'ing who was already in his seventies and knew nothing about the conduct of war. Chao-lien praised Ch'ai for his courage and perseverance in defending T'ai-wan-fu and Chu-lo and remarked that a number of famous commanders in the following decades owed their rise to the training and encouragement they received from Ch'ai.
[ 1/335/5a; 2/25/41b; Wei Yüan [q.v.], Shêng-wu chi, chüan 8; Chiang-shan hsien chih (1873), 9/27b; Tung-hua lu, Ch'ien-lung 51-3;淡水廳志 Tan-shui t'ing chih (1871), 11a-18a; Chao-lien [q.v.], Hsiao-t'ing tsa-lu, chüan 6; Davidson, J. W., The Island of Formosa (1903), pp. 78-81.]