Yingshi and Ligong

Authors: Boshun YANG

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Yingshi(also Shixiu) and Ligong in Stellarium

Yíng Shì (Encampment, 營室) is the thirteenth of the Twenty-eight Lodges and the sixth lodge of the Black Tortoise of the North. Its principal asterism contains two stars: the southern and determinative star is α Pegasi, and the northern star is β Pegasi. Ligong is a six-star auxiliary asterism beside Shi that is, as three pairs flanking the northern star of Shi. All eight stars lie within the modern constellation Pegasus.

Concordance, Etymology, History

The word shi 室 originally denoted an enclosed inner chamber used as a living space, while ying 營 carried the related meanings of encircling, construction, and a military encampment. The ancient name Yingshi 營室 could therefore evoke either a military camp or a walled palace compound, while also suggesting the construction of palaces and dwellings. The two stars of Shi and the two stars of Bi 壁 to its east together form what is now known as the Great Square of Pegasus. Early observers understood this spacious quadrilateral as marking the bounds of a palace compound or fortified encampment. The material imagery of the name and the visual form of the stellar configuration thus reinforced one another. By the early Warring States period, these four stars were treated collectively as Yingshi: the eastern pair was called Dongying 東營, the “Eastern Encampment,” and the western pair Xiying 西營, the “Western Encampment.”

The Erya 尔雅 states that “Yingshi is called Ding 定.” Guo Pu 郭璞 comments: “Ding means ‘correct.’ In constructing palaces and dwellings, people invariably took the culmination of Yingshi as their standard.” The line “When Ding was at culmination, construction began on the palace at Chu” (Ding zhi fang zhong, zuo yu Chu gong 定之方中，作于楚宫) in the “Yongfeng” section of the Book of Odes preserves the same body of seasonal knowledge. When Ding culminated in the evening sky, agricultural work had begun to slacken and the season was suitable for constructing palaces and dwellings. The name Yingshi may therefore have been connected with the asterism’s dual function in seasonal timekeeping and orientation during architectural construction.

Sima Qian’s 司马迁 Tianguan shu 天官书 (“Treatise on the Celestial Officials”) preserves astronomical knowledge from the early Han dynasty. Its statement that “Yingshi is the Pure Ancestral Temple; it is called Ligong and Gedao” (营室为清庙，曰离宫、阁道) indicates that, by the early Han period at the latest, the celestial region of Yingshi had already acquired multiple cultural interpretations. In other traditions, Yingshi also bore names or associations such as Xuanming 玄冥 (“Dark and Obscure”), Daren zhi gong 大人之宫 (“Palace of the Great Man”), military provisions, and Tianku 天库 (“Celestial Granary”).

The terrestrial term ligong 离宫 denoted a secondary or temporary palace situated apart from the principal palace and used for the ruler’s temporary residence, repose, and private life. It was perhaps on the basis of this familiar meaning that the Shi-school star tradition established Ligong as an auxiliary asterism of Yingshi. Ligong thereby became an independently identifiable asterism subject to astrological prognostication in its own right.

This process of differentiation also demonstrates that the Chinese asterism system was not created all at once as a complete and fixed scheme. Over the course of its long transmission, an established vocabulary of political institutions and material culture was repeatedly divided, reorganized, and projected onto the sky. In the present case, several cultural meanings formerly clustered around the celestial region of Yingshi were gradually differentiated into a principal asterism and its auxiliary asterism.

Identification of stars

From the Western Han dynasty onward, the stellar identifications of Yingshi—more commonly known in later periods as Shi Xiu (Lodge Encampment室宿)—and Ligong remained relatively stable, with no securely attested substantial changes.

	Star Names or Orders(Qing)	Han Dynasty (SUN X. & J. Kistemaker)	3rd to 6th Century (Boshun Yang)	Song Dynaty (Boshun Yang, 1034 CE)	Song Dynasty (Pan Nai, 1052 CE)	Yuan Dynasty (Pan Nai, 1279-1368)	Qing Dynaty (Yi Shitong, 18th Century)
Yingshi	1st	α Peg	α Peg	α Peg	α Peg	α Peg	α Peg
	2nd	β Peg	β Peg	β Peg	β Peg	β Peg	β Peg
Ligong	1st	λ Peg	λ Peg	λ Peg	λ Peg	λ Peg	λ Peg
	2nd	μ Peg	μ Peg	μ Peg	μ Peg	μ Peg	μ Peg
	3rd	ο Peg	ο Peg	ο Peg	ο Peg	ο Peg	ο Peg
	4th	η Peg	η Peg	η Peg	η Peg	η Peg	η Peg
	5th	τ Peg	τ Peg	τ Peg	τ Peg	τ Peg	τ Peg
	6th	υ Peg	υ Peg	υ Peg	υ Peg	υ Peg	υ Peg

Maps (Gallery)

historical map	modern identification	same in Stellarium
Yingshi and Ligong in Cheonsang Yeolcha Bunyajido	Yingshi and Ligong reconstructed by Boshun Yang	Yingshi and Ligong in Stellarium

IAU Working Group on Star Names

In 2026, the name of the historical constellation "Ligong" was suggested to be used for λ Peg in this constellation, because it was regarded as the first star in Qing dynasty.

Decision: ...

References

References (Chinese)