Altars for Ritual Offerings

Origin of the Offering Altar
Offerings originally referred to rites for rendering cults to deities performed in large-scale Daoist rituals. The Offering Altar originally referred to the Ritual Place ( 壇場 Tanchang ) where the Seats of Spirits ( 神位 Shenwei ) and the statues of spirits were set. After the Tang dynasty, fasts and offerings were performed together, so the difference between the Fasting Altar and the Offering Altar gradually faded. In ancient China, there already existed rituals for offering sacrifices to spirits. Giving offerings to spirits involved rendering cults to spirits, meaning "inviting the spirits of Heaven and Earth to enjoy the offerings". In the Wei, Jin, and the Southern and Northern Dynasties, Daoist rituals were fairly developed, hence the differentiation between "fasting" and " offerings" and the distinction between Fasting Altars and Offering Altars in the ritual space. It is cited in The  Daoist Book of Accordance with Spirits ( 道書援神契 Daoshu Yuanshen Qi ) that "altars were always set up at cult rituals in ancient time. In later ages, the prefectures had their altars to the gods. It is recorded that altars were not set up in houses. The ancient Offering Rituals were set up in the open, and the altars are set up in houses nowadays just for simplicity". After the Tang dynasty, fasts and offerings were conducted together, and after the Yuan and Ming dynasties, Fasting Altars and Offering Altars gradually became integrated. In today's Daoist rituals, the seats of the spirits are usually set at the same time as the rituals for saving the souls of the dead. The rituals of fasts and offerings are both performed, and the Fasting Altars and the Offering Altars are integrated. The places where the rituals are held are generally named the ritual place, or the Sacred Place ( 道場 Daochang ).

Arrangement
According to The Numinous Treasure Golden Book of Instructions on Aid and Salvation ( 靈寶領教濟度金書 Lingbao Lingjiao Jidu Jinshu ), "the Offering Altar refers to the seats arranged at an offering banquet". The Offering Altar is the place for offering sacrifices to the seats of spirits. In the centre of the altar, the seats of the Three Pristine Ones ( 三清 Sanqing ) are set up high. In front of the seats, a place of several chi is left for people to walk. In addition, the Seats of the Seven Heavenly Ministers ( 七御座 Qiyu Zuo ) are set up, and on each seat, there are signboards and small tables. On the left and right are the seats of spirits and sages. Two banquet places are linked together, and incense, flowers, lanterns and candles are offered according to rules. Three incense tables are set up from the centre to the outside, the outmost one for inviting sages, the second for holding the zodiacal light, and the one in the centre for assembling the offerings. If there are other spirits invited for salvation or averting by prayers, other seats of spirits will be set at the Offering Altar and "their order will be arranged" by the Daoist priests who conduct the ritual. At the ritual place where the Daoist priests nowadays perform rituals, the seats of the Three Pristine Ones and other spirits are always set up in the innermost space, and the incense table and offerings are also placed. The Fasting Altar for the performance of the ritual is established at the exterior of the ritual place. The seats of the souls of the dead to be saved are arranged in other places for the believers to offer sacrifices. 醮壇