石璋如
乙五基址的形狀如工字，分南、中、北三部。
南部設北、南兩齒輪，稱干支輪。北輪小，徑3公尺，10齒，代表天干；南輪大，徑9公尺，12齒，代表地支。輪齒相交，小輪一周十日，為一旬，三周為一月；大輪一周十二日，五周六十日為一甲子。兩輪轉動不息以紀日，即所謂干支紀日。
中部設東西兩行柱子，相距9公尺，稱月象柱。東行8柱，西行7柱，但東行1柱之西另有1柱，共16柱。因回轉程序乃稱16為30。除1與30兩柱為單面使用外，其餘各柱均為兩面使用。東行1柱為新月，8柱為上弦，西行15柱為滿月。轉回至22為下弦，繼續前進，若為小月至29止，若為大月則用30，周而復始以紀月。此外，1及30二柱居最南，或謂月宮，稱內宿，宮外各柱稱外宿，這種設施或與二十八宿起源有關。在3柱旁之大白陶酉，為觀察天象的設施。
北部由七個墓葬的排列，推知7個大灰陶酉的位置，由西而東排列如同天上北斗的樣子，可稱為北斗酉。器後，或一器一井，或二器一井，以便隨時供給器內之用水，可由水中觀察天上的星辰，並隨時測視天上北斗之旋動以紀年。確定天上的星位與地上的星位相照時，正是農曆九月的天象，也就是秋嘗大祭的時間。
此外在YH019與YH020內居者監視輪轉，在YH061與X：H1內居者監視月變，在4：H9及YH034內居者監視斗旋，在YH006內居者觀察占卜，在X：H2內居者指極定斗，這些人等並與東部之測影台人員（乙一及乙三基址），日夜相繼，工作不停，以進行殷代的曆象。
關鍵詞：干支輪
月象柱 日食酉
北斗酉 指極定斗
The
Ninth Example of Ground-level Architectural Reconstruction at Yinxu, with a
Discussion of the
Astronomical Symbolism of B5 Foundation
Chang-ju
Shih
Institute of History and Philology, Academia Sinica
The B5 foundation is “工” shaped. It is divided into three sections: north, center and south.
The southern section contains two spoked wheels, positioned north and south, which are termed ‘sexagesimal wheels’ ganzhi lun. The smaller northern wheel, 3 meters in diameter, has 10 spokes, marking the 10 celestial stems, tiangan. The larger southern wheel, 9 meters in diameter, has 12 spokes, marking the 12 terrestrial branches, dizhi. The two wheels are connected. The smaller one completes one revolution in 10 days, marking a decade called xun. Three revolutions mark one month. The larger wheel completes one revolution in 12 days, and the 60 days completed in five revolutions correspond to one full sexagesimal cycle. The ceaseless revolutions of the two wheels mark the time – hence, they are termed ganzhi jiri.
The central section contains two juxtaposed rows of pillars running east to west and positioning nine meters apart. These pillars are termed ‘lunar-phase pillars’, yuexiang zhu. The eastern row has 8 pillars, and the western has 7 pillars. There is another pillar to the west of pillar 1 of the eastern row, thus making a total of 16 pillars. Returning through the sequence of the 16 pillars marks 30 days. All the pillars utilize both faces except pillars 1 and 30 which utilize only one face. Pillar 1 of the eastern row signifies the new moon, and pillar 8 signifies the first quarter, shangxian. Pillar 15 of the western row signifies the full moon. Counting back, pillar 22 indicates the third quarter xiaxian. Proceeding to the final markers, pillar 29 marks a short month, while pillar 30 marks a long month. A full cycle of these pillars marks a full month. Pillars 1 and 30, at the southern end of the two rows, termed Lunar Palace (Lunar Lodges) (yuegong), are also known as the Inner Lodges (neixiu). The pillars outside this ‘palace’ are termed Outer Lodges (waixiu). This structure is probably related to the origins of the 28 lunar lodges (constellations). A large white clay vessel (taoyou) at the side of pillar 3 was used for astronomical observation.
The northern section contains a row with 7 tombs, by which we can reconstruct the positions of 7 gray clay vessels (taoyou). As these vessels were arranged in the form of the northern dipper from west to east, we term this arrangement the Northern Dipper vessel (you). Behind each vessel, there are either single or double wells. Water could thus be placed into the vessels whenever required. Astronomical observations could be made by observing the reflection in the water. Thus the rotation of the Northern Dipper could be calculated in order to calculate a year. Determining the correspondence of the stars and their terrestrial indicators was to be done on the ninth month of the agricultural calendar. This was the time of the Great Ancestral Sacrifice.
Furthermore, residents at YH019 and YH020 observed the revolving wheels. Residents at YH061 and at X：H1 observed the lunar changes, and at 4：H9 and YH034 residents observed the rotation of the dipper. At YH006 the residents observed divination, and the resident at X：H2 was ‘dipper determinant’ (zhiji dingdou) . These individuals, together with the observers at the Shadow Measuring Platform (ceying tai) (in foundations B1 and B3) continuously worked at their observations by which to determine the calendar of the Yin dynasty.
Keywords:
‘sexagesimal
wheels’
ganzhi lun, ‘lunar-phase
pillars’
yuexiang zhu, Eclipse vessel, Northern Dipper vessel, ‘dipper
determinant’
zhiji dingdou