Regency (shezheng 攝政) was a legal means to hold up government affairs for a child emperor (nian you 年幼) or if an emperor was seriously ill. It was executed by one or several persons.
The paradigm of a regent was the Duke of Zhou 周公, who during the early Western Zhou period 西周 (11th cent.-770 BCE) reigned (jianzuo er zhi 踐阼而治 "he rose the steps [to the throne] and arranged [political matters]", from Liji 禮記, ch. Wenwang shizi 文王世子) for the young ruler King Cheng 周成王 (trad. r. 1116-1079 BCE).
In his book Xinyu 新語, Lu Jia 陸賈 (240-170) explained that a regent (fuzheng 輔政) was someone with a "high standing like a Saint" (yi shengren ju gaochu shang 以聖人居高處上) and used to govern with "kindheartedness and righteousness" (yi ren yi wei chao 以仁義為巢) in order to steer through dangers "with the stave of a Saint and worthy" (yi shengxian wei zhang 以聖賢為杖). A good regent was a person of softness, warmth, and austerity.
In fact, contemporaries of the Duke charged him attempted usurpation. His regency initiated a debate over the role of ministers in the Zhou kingdom, in which the Duke of Zhou gave privileges to ministers over kings, while the Duke of Shao 召公 supported the king's prerogative to rule as the Son of Heaven (Shaugnessy 1993).
There are indeed several cases in history, when a regent replaced the ruling dynasty, for instance, Wang Mang 王莽 (45 BCE-23 CE), who overthrew the Former Han 前漢 (206 BCE-8 CE) and founded the Xin dynasty 新 (8-23 CE), or Cao Pi 曹丕 (187-226), who ended the Later Han 後漢 (25-220 CE) and founded the Wei dynasty 魏 (220-265).
In the early imperial age, the Empress Dowager (huanghou 皇后), the widowed primary consort of a deceased ruler, took normally over regency. The most famous examples are Empress Dowager Lü 呂太后 (d. 180 BCE) from the early Former Han, Empress Wu Zetian 武則天 (regent 684-690, ruler 690-704) from the Tang 唐 (618-907), and Empress Dowager Cixi 慈禧太后 (1835-1908) from the late Qing 清 (1644-1911) period.
Yet there are also plenty of examples when brother or other close relatives of empresses dowager took over regency, particularly during the Han period, as for instance, Huo Guang 霍光 (d. 68 BCE) or He Jin 何進 (d. 189 CE).
During the early Qing, a consortium of regents run the state during the youth of the Shunzhi 順治帝 (r. 1643-1661) and the Kangxi 康熙帝 (r. 1661-1722) emperors. The most famous of these regents were Dorgon (1612-1650) and Oboi (c. 1610-1669). Zaifeng 載灃 (1883–1951), Prince Chun 醇親王, reigned for his son, the three-year old Xuantong Emperor 宣統帝 (r. 1908-1912).
When a young emperor came of adulthood he "personally took over the government" (qinzheng 親政).
The term shezheng was still used in the Republican era (1912-1949), when the cabinet (neige 內閣) took over the executive if the post of President (da zongtong 大總統).
The regency of an empress dowager was called linchao chengzhi 臨朝稱制 "face the court and pronounce edicts" or linchao tingzheng 臨朝聽政 "face the court and listen to governmental affairs", even if this expression is normally used for an active ruler. The commentator to the official dynastic history Hanshu 漢書, Yan Shigu 顏師古 (581-645), explains that there were two types of documents issued by an emperor, namely edicts or decrees (zhishu 制書), and proclamations or announcements (zhaoshu 詔書). A reigning empress dowager was actually not allowed to pronounce edicts. This argument is directed (unless Yan's argument is wrong) against Empress Dowager Lü from the early Former Han period, but would also perhaps refer to Empress Dowager Liu 劉太后 (Empress Zhangxian 章獻后, 968-1033), who reigned "by pronouncing edicts" (linchao chengzhi) for the Song 宋 (960-1279) emperor Renzong 宋仁宗 (r. 1022-1063).
The regency of an empress dowager was a common and legal means of securing the regular process of day-to-day government. During the late Qing period, Empress Dowagers Ci'an 慈安太后 (1837-1881) and Cixi, primary and secondary consorts of the Xianfeng Emperor 咸豐帝 (r. 1850-1861), were several times formally invited to take over regency for a young emperor, first for Cixi's son, the Tongzhi Emperor 同治帝 (r. 1861-1874), and then two times for her nephew, the Guangxu Emperor 光緒帝 (r. 1874-1908). Yet in practice, the daily business of government was first carried out by a consortium of Eight Regents (guming ba da chen 顧命八大臣) consisting of Princes and ministers. Yet this consortium was soon dissolved, and the Princes Gong 恭親王 (Ihin 奕訢, 1833-1898) and Chun 醇郡王 (Ihuwan 奕譞, 1840-1891, both being uncles of the emperor) took over regency.
During the childhood of the Guangxu Emperor, statues regulated the female regency (Taihou chuilian zhangcheng 太后垂簾章程). As the regency was nominally carried out by the two Empresses Dowager, the circumstance was called "regency by the two palaces" (lianggong tingzheng 兩宮聽政). In 1881, Empress Dowager Ci'an passed away, allowing Cixi to reign alone until 1888. Ten years later, the Emperor's reforms (see Hundred Days' Reform) were ended by a conservative coup d'état, and Cixi again took over regency in the form of "instructive government" (xunzheng 訓政).
The formalities to be observed were similar during the Song period, when Empress Meng 孟氏 (primary consort of Emperor Zhezong 宋哲宗, r. 1085-1100) was asked to reign for two short intervals in 1127 and 1129. She played an important role in securing the accession to the throne of Emperor Gaozong of the Southern Song.
Since the Tang period it was common that reigning Empress Dowagers sat behind a bamboo curtain (lian 簾) during court sessions and audiences. The ususal term for a female regency is therefore usually chuilian tingzheng 垂簾聽政 or chuilian tingjue 垂簾聽決 "listening to and deciding over policial affairs from behind the curtain". Empress Wu Zetian was perhaps the first female regent who sat behind a curtain hanging down from behind the throne (yuzuo hou 御座後). Even if her husband, Emperor Gaozong 唐高宗 (r. 649-683), was ruling actively, she assisted him so much that she was called the "Second Holy [Ruler]" (ersheng 二聖). The was the first and only female regent who eventually took over the position of the emperor.
The "ceremony of the hanging curtain" (chuilian yi 垂簾儀) was an official form of congratulatory rites (jiali 嘉禮, see five rites). At the time of the enthronement of the Tongzhi Emperor, the curtain was apparently just a relict from ancient times. Empress Dowagers Ci'an and Cixi received documents and decided in front of the curtain, and not behind. Quite interestingly, it was the Guangxu Emperor who was hidden behind a satin screen (shaping 紗屏) with the two regenty as long as he had not taken over government affairs. Each document was formally submitted in three copies, so the emperor and the two female regents had formally one at hand.
The term jianguo 監國 "supervisor of the state" was mainly used for temporary regents overseeing government business when the emperor was outside the capital, for instance, during a military campaign or on an inspection or hunting tour. The function was usually carried out by the Heir Apparent or a high dignitary, in case of the Emperor Chengzu's 明成祖 (r. 1402-1424) campaign in 1410 even by the Imperial Grandson (huang zhangsun 皇長孫). The term was first used in the history book Guoyu 國語 (ch. Jinyu 晉語 1) and the Classic Zuozhuan 左傳 (Mingong 閔公 2).
The word zhizheng 執政, lit. "hold the government" was an ancient expression for control over government affairs by an individual official and his clients. This was not illegal, but might have the connotation of unjust dominance over potential rivals. The word is even used as a neutral term in the sense of "to execute government affairs". One example for a negative use is the abuse of power by court eunuchs during the Later Han period. They "dominated" the government without having government positions. The word zhizheng was used as a verb as well as for the persons in power.
During the Song period, zhizheng became an official designation of a function and was a general reference to vice grand cousellors (fuxiang 副相) serving in the Administration Chamber (zhengshi tang 政治堂) where the most important central government decisions were made; all held primary appointments in the Secretariat-Chancellery (zhongshu menxia sheng 中書門下省) or the Bureau of Military Affairs (shumiyuan 樞密院). (Hucker 1985: 939). The word designated all high officials of the inner circle of the government – apart from the Counsellor-in-chief (zaixiang 宰相), namely Vice Grand Counsellors (can zhizheng shi 參知政事), Military Affairs Commissioners (shumishi 樞密使), Vice Military Affairs Commissioners (shumi fushi 樞密副使), Notaries of the Bureau of Military Affairs (qianshu shumiyuan shi 簽書樞密院事), Administrators of the Bureau of Military Affairs (zhi shumiyuan shi 知樞密院事), Associate Administrators (tongzhi shumiyuan shi 同知樞密院事), Left and Right Aides in the Imperial Secretariat (shangshu zuocheng 尚書左丞, shangshu youcheng 尚書右丞), Vice Directors in the Palace Secretariat (zhongshu shilang 中書侍郎), and Vice Directors in the Chancellery (menxia shilang 門下侍郎).
The Jurchen-Jin dynasty 金 (1115-1234) used the word as an alternative name for the Left and Right Aides in the Imperial Secretariat and the Vice Grand Councilors, and the Yuan 元 (1279-1368) as a synonym of the Left and Right Aides of the Palace Secretariat (zhongshu zuo cheng 中書左丞, zhongshu youcheng 中書右丞). All of these posts were defined as "assistants" to the Counsellor-in-chief.
The word zhizheng was still used in 1924, when the warlord Duan Qirui 段祺瑞 (1865-1936) created a provisional cabinet (linshi zhengfu 臨時政府), in which he held the post of "executive head" (zhizheng 執政).
The term zhuanzheng 專政 has two meanings. The stronger sense is that an individual person and his clansmen dominate political affairs and the executive, like the family Luan 欒 in the state of Jin 晉 or the Three Huan families 三桓 in Lu 魯 during the Spring and Autumn period 春秋 (770-5th cent. BCE), or Wang Mang during the late Former Han period. This meaning has a slight connotation of illegality, even if the dominant officials hold their functions rightfully. In modern Chinese therefore, the word zhuanzheng means "dictatorship". In a weaker sense, the term zhuanzheng just means "to act as an executive, to reign" (same as zhizheng 執政). The Chinese term for an usurpation or illegal interferenct into the executive was shanzheng 擅政.