The book under review is a revised version of Jia Lianxiang's PhD dissertation at Tsinghua University on the so-called shuzi gua 數字卦 corpus, a large set of unearthed texts dating from the Longshan Culture (c. 3000–1900 bce) to the late Warring States period (475–221 bce). The term shuzi gua (numerical divinatory symbol, or numerical gua) refers to a sequence of specific integers – 1, 4, 5, 6, 7, 8, and 9 – stacked one on top of the other in groups of three (sanyao gua 三爻卦), four (siyao gua 四爻卦), six (liuyao gua 六爻卦), or pairs of six (lianglie liuyao gua 两列六爻卦). Roughly one hundred instances of these symbols have been found on various types of unearthed artefacts, including ox scapula, turtle shells, bronzes, pottery handles, and bamboo slips. Due to the presence of numbers and the gua-like shape, these symbols are usually regarded by scholars as ancestral to the Zhouyi 周易 (Zhou Changes, or Yijing 易經, Book of Changes, or simply Yi 易), a divination manual which was canonized in 136 bce. Its basic constituent are the 64 hexagrams, i.e. six-line diagrams which purportedly owe their symbolic origin to the ancient Chinese cosmic concept of the Two Primary Forces: yin 陰 (represented by even numbers and the “broken line”), and yang 陽 (represented by odd numbers and the “unbroken line”). The first scholar who systematically linked the shuzi gua to the Zhouyi was Zhang Zhenglang 張政烺 (“Shi shi Zhouchu qingtongqi mingwen zhong de Yigua” 試釋周初青銅器銘文中 的易卦 [A Tentative Interpretation of the Yi Gua on the Early Zhou Bronze Inscriptions], Kaogu xuebao 考古學報, 1980/4, 403–15). Since Zhang's ground-breaking article and the increasing acquisition of shuzi gua materials, scholarship on this topic has thrived, and Jia's monograph represents the most up-to-date and comprehensive synthesis in the field of pre-Qin Yi studies.

The book consists of five main chapters, in addition to an introduction and conclusion, as well as three appendices (one at the end of chapter 1 and two at the end of chapter 2). In the introduction, Jia introduces the terminology and methodology employed for the analysis of the primary sources. It also provides a definition of the shuzi gua and a brief overview of the existing scholarship.

Chapter 1 is a detailed study of stalk divination and development of the Yi tradition, starting from a reconsideration of the Zhouyi and its commentary in the light of the manuscript versions. This chapter is divided into seven sections; it covers some of the most important historiographical and philosophical texts, such as the Zuozhuan 左轉 and the Xunzi 荀子, spanning the pre-Qin period and the Han dynasty. Interestingly, Jia divides the divinatory cases in the Zuozhuan and Guoyu 國語according to the different states; this analysis nicely integrates Kidder Smith's study (“Zhouyi interpretation from accounts in the Zuozhuan”, Harvard Journal of Asiatic Studies 49/2, 421–63. https://doi.org/10.2307/2719259).

Chapter 2 is a catalogue of 88 items, for a total of 138 examples of what Jia defines as shizhan shuzi gua 實占數字卦 (actual divination result), which, as stated in the introduction, should be distinguished from the guahua tuxing 卦畫圖形 (trigram/hexagram pictures). The items are catalogued according to date, object type, and geographical area. This chapter sees two major improvements from Jia's PhD thesis. First, the information for each item is now clearly divided into 1) dating, 2) measurement, 3) archaeological context, 4) transcription, and 5) additional notes; the latter are mostly concerned with palaeographical considerations. Second, the presence of high-resolution photographs (though not for each item) allows for a better appreciation of the original inscriptions; this represents a useful tool as scholars sometimes disagree on how to transcribe archaic graphs.

Chapter 3 is a thorough study of the main issues related to the shuzi gua corpus. Jia first discusses the computational methods employed to calculate the gua. Drawing on Li Xueqin's 李學勤 hypothesis of the two stalk systems, Jia first outlines the 1-system and 7-system; he then argues that the Warring States bamboo divinatory records should belong to the 1-system. Next, he explores the differences and commonalities between the shuzi gua and the philosophical tenets of the Yi tradition. While recognizing clear structural and visual links between the two divinatory traditions, Jia points out that these links become difficult to identify within the earlier material.

Chapter 4 focusses on the Shifa 筮法 (Method of stalk divination), a Warring States bamboo manuscript of the ancient state of Chu 楚, now part of the “Tsinghua bamboo slips” collection. Jia conveniently provides the original pictures of the bamboo slips along with an accurate transcription of each of the manuscript's 30 sections.

Chapter 5 concerns the shuzi gua from the Warring States Chu area. Jia first analyses the divinatory records of the Baoshan 包山, Tianxingguan 天星觀, and Xincai 新蔡 bamboo manuscripts according to the Shifa system, reaching the conclusion that they belong to the same divinatory tradition. He then attempts a reconstruction of the ancient computational method, proposing a modified version of the one described in the received Xici 繫辭 (Commentary to the Appended Statements [of the Yi]). Jia argues that the traditional computational method of the Xici must have developed within the state of Chu. Finally, he proposes that the Shifa might be related to the Lianshan 連山 (Joint Mountains), one of the three traditional Yi texts.

The conclusions summarize the main argument of the book in seven points. In his final remarks, Jia stresses that his conclusions are inevitably provisional and cannot be considered as the definitive understanding of such a complex and heterogeneous corpus of texts; further research is in order as new palaeographical sources will be discovered. Although his arguments are avowedly tentative and at times not entirely convincing – the 1- and 7-systems hypothesis does present problematic aspects, namely the discussion on the coexistence of numbers 1 and 7 in the same shuzi gua – Jia's monograph undoubtedly represents a fundamental contribution, and will surely become a seminal work in the field of pre-Qin Yi scholarship.