The Lore of Chinese Seals
Yeh Ch'iu-yuan 葉秋原
This essay takes extends our discussion of West Lake, but by introducing the world of seal carving, a focus of the West Lake Seal Society West Lake Seal Society (Xiling Yinshe 西泠印社) on Solitary Hill 孤山. This piece is reproduced from T'ien Hsia Monthly, Vol.X, No.1, January 1940. Minor stylistic changes have been made in keeping with the format of China Heritage Quarterly. We have also perpetrated an anachronistic simplification by changing the spelling of Yeh's original to conform with standard Hanyu pinyin for the convenience of latter-day students of China.—The Editor
To those of us who have visited Hangchow, which together with Soochow is known as 'paradise on earth', the memory of the tranquil lake and lovely hills surrounding the lake will never be easily forgotten. While we may not all agree that the so-called ten beauty spots of the West Lake are really beautiful—for indeed at least two or three of them have, since the days of Emperor Qianlong, ceased to be beautiful in the ordinary sense of the word—there are nevertheless other places which will always afford delight to the visitors. Among these, one is known as the West Lake Seal Society (Xiling Yinshe 西泠印社). Situated next to the old imperial palace on the left side of the Imperial Hill, which stands in the middle of the lake and is connected with the lake shore by two dykes said to have been built by two famous Chinese poets, Bai Juyi and Su Dongpo, the Seal Society commands a very fine view of the lake and the surrounding hills. Inside the compound of the Society there are halls, pavilions, statues, stone tablets, rock inscriptions, pines and bamboos, which combine to give an air of tranquility which typifies the Chinese garden. Founded in 1904 by a group of Hangchow literati, the Society is unique, for nowhere else in China can we find another like it. That such a society should be founded in Hangchow has, of course, its reasons.
Fig.1 Deng Shiru (鄧石如, 1743-1805), founder of the Deng school of seal cutting
To begin with, in the eyes of the Chinese literati the art of seal cutting is as much an art as painting and calligraphy. A good Chinese painting must be matched by good calligraphy and good seal marks, in addition to good poetry which a Chinese artist usually inscribes on his paintings. For this reason Chinese literati value their seals immensely. They would collect seals as they collect paintings and samples of calligraphy. Apart from the art of painting and calligraphy, there is, therefore, a special art of seal cutting in China, which is sometimes known also as the art of the 'Iron Pen' 鐵筆.
In the history of the art of seal cutting Hangzhou gave birth to what is known as the Chekiang School 浙派, with which we shall deal in detail later on in the article. From the early years of the Ch'ing dynasty, a number of famous seal artists who revived the art of seal cutting were born there, and to perpetuate their memory, the West Lake Seal Society was founded. Thus, in the art of seal cutting, Hangchow has a tradition of its own.
The tradition of seal cutting in China, however, dates back to the pre-Christian era. In his preface to the catalogue of seals In Ge Qian's 葛謙 collection, Zhu Yizun (朱彝尊, 1629-1709) points out that the origin of the Chinese seal should go further back than the time of Qin 秦, which was usually considered as the time when the use of seals began. According to Zhu, a seal is but a mark of credence (印者信也); therefore he holds that the history of the Chinese seal should really begin with the Zhou. There was in the Zhou dynasty a government bureau known as Zhangjie 掌節, whose duty it was to look after the seal of state known as bangjie 邦節. Another kind of seal then in vogue was known as xijie 璽節, which was issued by the office of Sishi 司市 and was used as a kind of token money in business transactions. In Zhou's time, then, there were only two kinds of seals: one belonging to the state, the other issued by a government agency for business transactions. No private individuals were, therefore, allowed to have seals of their own. This rule, however, was later abandoned; so by the time of Eastern Zhou, officials of state who received two hundred piculs of rice a year were allowed to have their own seals.
With the establishment of the Qin dynasty, seals definitely became an institution of state. In place of bangjie, the Qin emperor ordered that six seals of state be made to commemorate the establishment of the empire and to mark the ascension of the Son of Heaven to the Throne. Seals of state were then made of jade, which was forbidden to be used by other persons. The following inscriptions were formed on these seals: 1. Huangdi xingxi 皇帝行璽; 2. Huangdi zhi xi 皇帝之璽; 3. Huangdi xinxi 皇帝信璽; 4. Tianzi xingxi 天子行璽; 5. Tianzi zhi xi 天子之璽; and, 6. Tianxi xinxi 天子信璽. Upon the discovery of a fine piece of jade in Lantian藍田, the Qin emperor ordered his minister Li Si 李斯 to make it a seal of state and to cut thereon the following characters: 受天之命既壽且昌, meaning: 'Appointed by Heaven to Enjoy Longevity and Prosperity'. Of these seven seals, it was said that the one on which were the characters Tianzi zhi xi was worn by the emperor on his person as a mark of authority. The other six seals were left to the safe-keeping of a governmental organ which corresponded to what was later known as the Ministry of the Imperial Household.
Besides these seals of the emperor, officials of state were also allowed to have seals, but with this difference: whereas in the case of imperial seals it was known as xi 璽, those of the officials were only known as yin 印, the former being made of jade, the latter of bronze. Thus began the use of the character yin, which has prevailed to this day.
Fig.2 Some Han seal marks on clay. Clay was used in the Han Dynasty as a sort of sealing wax.
The institution of chuanguo xi 傳國璽 also was introduced in the Qin dynasty. Upon the establishment of the Han dynasty, the crown prince of Qin handed to Han Gaozu (漢高祖, 201-195BC), the first emperor of the Han dynasty, the Qin seal on which appeared the inscription: 'Appointed by Heaven to Enjoy Longevity and Prosperity'. After his enthronement as emperor, Han Gaozu always wore this seal on his ceremonial dress. The seal was handed down to successive generations of emperors and was regarded as a symbol of imperial authority. Connected with this seal there was a very complicated history, the details of which we need not go into here. Suffice it to say that the seal was lost during the troublesome time of Jin 晉, and the Jin rulers were ridiculed as being emperors with only a white slab (baiban tianzi 白板天子), meaning that they had no imperial authority and were not appointed by heaven.
However, though the original Qin seal was lost, a new one was made and the institution of chuanguo xi became thus firmly established.
With the establishment of the Han dynasty, the art of seal cutting reached its golden period. There was then established in the office of Siyushi 侍御史, a Department of Seals (yincao 印曹), whose duty it was to make seals for the emperor, the imperial household, and various officials. Seals of the emperor continued to be made of jade and those of the officials, of bronze. Besides the Department of Seals, there were also seal experts attached to the expeditionary forces that were frequently sent to different places. So throughout the long period of the Han dynasty, a countless number of seals were made, among which, however, a difference in technique could be detected. Due to the fact that seal experts attached to the expeditionary forces had only a limited time at their disposal for seal making, their seals were often hastily done. They abandoned the technique of moulding employed by the Department of Seals in the office of Siyushi, and started the practice of cutting directly on the bronze surface of the seals. The Han seals can, therefore, be grouped under two categories: moulded seals and cut seals. The difference can, of course, be readily seen. The seals which were moulded are usually of a finer composition with heavier strokes, while the cut ones usually give an appearance of roughness with lighter strokes.
In connection with the seal, there was evolved in the Han dynasty an elaborate system of doctrines and traditions. Thus, besides the seal proper, there was evolved a system of shou 綬, or the cord fastened on the seal, and niu 鈕, that is, the carved, or moulded, object on top of a seal through which the cord passed. Since there were seals for the emperor, the empress, members of the imperial household, and different grades of officials, so there were also different kinds of shou and niu to match. According to the rules in use in the Han dynasty, the emperor's seal had a tiger niu and a shou made of silk threads in five colours, namely yellow (which was the dominating colour), red, deep green, light green, and white, having a length of two zhang (丈) and nine chi (尺). The seal of princes had a camel niu and a shou in four colours, namely red, yellow, deep green, and light green, having a length of two zhang and eight chi. The seal of a minister or a general had a turtle niu and a shou in purple and white, having a length of seven ch'ih. Besides these prescribed rules, there were other rules pertaining to the seal, the shou, and the niu used by different grades of officials, which we need not go into here. Suffice it to say that no official who received less than two hundred piculs of rice a year was allowed to have a seal complete with a shou and a niu.
Apart from the rules regarding the use of shou and niu, there were other rules followed by the Han seal cutters. First, only the emperor's and the prince's seals were allowed to use the character xi 璽, while all others were either known as yin 印, or zhang 章, or by combining the two characters together, yin zhang 印章. Secondly, during the reign of Emperor Wudi (武帝, 140-87BC), all seals must contain five characters instead of the usual four by adding to them the character zhi ¬之. Thus, the seal of a minister would read Chengxiang zhi yinzhang 丞相之印章, instead of the usual Chengxiang yinzhang 丞相印章.
The reason why the emperor's seal had a shou in five colours with yellow as the dominating colour, and the number of characters cut on the seal was five is this: In the early Han dynasty, there was in vogue a system of doctrines known as the yin and the yang and the Five Elements. No one knows exactly when these doctrines originated, though they are generally attributed to the speculations of a certain Zou Yan 鄒衍, a contemporary of King Hui of Wei (魏惠王, 370-55BC). At any rate, the system was already in existence when the Han dynasty was founded. According to this system, the Five Elements of Metal, Wood, Water, Fire and Earth were the manifestations of the yin and the yang. They form a cycle which constantly renews itself. Earth is vanquished by Wood, which yields to Metal, which succumbs to Fire, which is quenched by Water, which in turn is overcome by Earth, and so renewing the cycle. It was held that each dynasty reigned by virtue of one of the Elements, and fell when the predominance elapsed and gave rise to the succeeding Element. The Qin claimed to rule by virtue of Water, hence the Han dynasty which followed it was supposed to rule by virtue of Earth, the colour of which is Yellow and the number Five.
Throughout the long period of the Han dynasty, these rules were, to be sure, not always followed. For instance, during the reign of Emperor Wendi (文帝, 179-154BC) and that of Wang Mang (王莽, AD 8-24) new systems were introduced. But they were short-lived and cannot be taken as those of the Han.
In the Han dynasty, too, it was the fashion to bury the seal with the dead. It was mainly due to this custom that since the Han dynasty thousands of Han seals have been unearthed.
With the fall of the Han dynasty, the art of seal cutting gradually came to decay. The established authority was gone, with the result that people acted as they pleased. While it was the rule in the Han dynasty that only officials who received more than two hundred piculs of rice a year were allowed to have seals, the practice was no longer observed after the collapse of the Han dynasty so that even common people who had no official post could have seals of their own. Moreover, the sort of inscription on the seal also changed. In the Han dynasty, only one's name or official post appeared on the seal; but by the end of the Jin dynasty, the so-called 'leisure seals' (閒章 i.e., seals on which were cut not one's name or official post but an irrelevant phrase, or a sentence taken from a poem, or the name of one's villa or hut, etc.) came into fashion. The system of official seals was gone, and with it also the art of seal cutting.
So by the time of the Tang dynasty, seal cutting had almost become a lost art. Although the system of official seals was reinstituted with some modifications, the art of seal cutting never reached the level of perfection that was the Han's. The art of seal cutting received further condemnation by Zhu Xi (朱熹, 1130-1200) and his school, who expounded the doctrines of Confucianism in the Song dynasty. According to them, Chinese scholars should refrain from indulging in hobbies that would kill their ambitions (玩物喪志). Seal cutting as such was condemned. But it was also in the Song dynasty that an attempt was made to collect the then existing Han seals and have their rubbings made and published in the form of a catalogue known as the Xuanhe Yinpu 宣和印譜, which has since become a treasure for Chinese seal lovers. In the Song dynasty, too, seals to mark the ownership of books were very much in use, so seals also became known as Tushu 圖書, which was taken from the last two characters cut on the seal, as for instance, Yufu Tushu 御府圖書, meaning 'From the Imperial Library'.
Not until late in the Ming dynasty was there a revival of interest in the art of seal cutting. There was at that time a group of literati in Suzhou who interested themselves in the arts of painting, calligraphy, and seal cutting, among whom were such illustrious personages as Wen Zhengming (文徵明, 1470-1559) and Tang Yin (唐寅, 1470-1523). They devoted their leisure time to the study of the old masters, and became celebrated artists in painting and calligraphy. And it was mainly due to their efforts that the art of seal cutting was revived. For, under their tutelage, there appeared modern masters of the art of seal cutting, one of whom was none other than the son of Wen Zhengming.
Fig.3 Xi Gang (奚岡, 1746-1803), one of the Eight Great Seal Artists of Hangzhou
To the students of the Chinese seal, the names of Wen 文 and He 何 are like Michelangelo and Raphael to the students of Western painting. In fact, it was Wen and He who revived the lost art. Previous to their time, the art of seal cutting had, through centuries of neglect, degenerated into a mere craft; there was nothing artistic about it. Under the guidance of his father, Wen Zhengming, Wen Peng (文彭, 1498-1573) began the study of the art of seal cutting from old Han seals. His art reached such a state of perfection that all subsequent sear lovers treasured his works dearly. Aside from Wen Peng, there was another master, He Zhen 何震 who together with Wen Peng had been commonly regarded as the fathers of modern Chinese seal cutting. Born in Huizhou in the province of Anhui, He went to Nanjing, where he met Wen and there the two studied the art of old Han seals together. Around Wen and He, there gathered a host of literati interested in the art of seal cutting such as Wen Jia (文嘉, 1501-1583), Gui Changshi 歸昌世, and several others. With such a group of literati, and with both Wen and He holding official positions and enjoying reputations of their own, the art of seal cutting was lifted from a mere craft to a position of respect.
The School of Wen Peng and He Zhen is noted for its delicate strokes and since their time the art of seal cutting had evolved to a state which finds its parallel in the Rococo period of western art. Delicate lines were over-emphasised to such an extent that instead of being delicate they appeared to be unnecessarily intricate. As in the case of western art, the art of the Rococo was replaced by that of Neo-classicism, so in the history of the Chinese seal we also find that there were reactions against this tendency towards an over-emphasis of delicate lines. Thus, by the Qing dynasty, there arose several schools of seal cutting which had as their common purpose the return to the spirit of the Han seals, i.e., a sort of Neo-classicism in the art of Chinese seal cutting.
Among the various schools of seal cutting which had sprung up in the Ch'ing dynasty, the most famous is the Zhejiang School 浙派. Founded by Ding Jing (丁敬, 1697-1768), the Zhejiang School had as their aim the restoration of the art of seal cutting to a higher level than that which prevailed at that time. Lines of characters cut on the seal were simplified after the Han fashion. Consequently, the movement received nation-wide favour; and such persons as Weng Fanggang (翁方綱, 1733-1818), one time Prime Minister under the reign of Emperor Qianlong, and Ruan Yuan (阮元: 1764-1849) all supported the movement. A group of Hangzhou men followed in the footsteps of Ding Jing, and became known as the Eight Great Seal Artists of Hangzhou 西泠八大家. They are: Jiang Ren (蔣仁, 1742-1795), Huang Yi (黃易, 1744-1801), Xi Gang (奚岡, 1746-1803), Zhao Zhichen (趙之琛, 1781-1806), Qian Song (錢松, ?-1860), Chen Hongshou (陳鴻壽, 1768-1822), and Chen Yuzhong (陳豫鐘, 1762-1806).
Simultaneous with the rise of the Zhejiang School, there appeared also the Anhui School 皖派 or the Têng School 鄧派, so named because its founder was one Deng Shiru (鄧石如, 1743-1805). We have seen that the art of seal cutting in China owed its revival to many artists from Anhui, the most important of whom was he Zhen. He and Wen Peng have both been regarded as the father of modern Chinese seals. Since He's time, many seal artists from Anhui had over-emphasized the importance of delicate lines with the result that the art deteriorated. The appellation, Anhui School, had indeed existed long before Deng Shiru, but it was Deng who brought the name of the Anhui School to prominence. He simplified the lines of characters cut on the seal, though retaining, to a lesser extent, the intricate lines treasured by all Anhui seal artists. After Deng Shiru, the tradition of the Anhui School of seal cutting was carried on by such famous artists as Bao Shichen (包世臣, 1775-1855) and Wu Tingyang (吳廷颺, 1799-1870). Although both the Zhejiang School and the Anhui School, or the Deng School, worked after the fashion of the Han seals and had as their aim the simplification of lines, there is, yet, between them this difference in emphasis: the Zhejiang School is characterized by the use of straight lines, while the Anhui School is characterized by the use of curved lines.
Besides these two schools, there is still another school known as the Fujian School 閩派. Founded by Lian Yuansu 練元素, Xue Quan 薛銓, and Lan Lian 藍漣, the Fujian School found its best expression in the art of Yi Bingshou (伊秉綬, 1754- 1815). A famous calligraphist, Yi Bingshou also cut seals after the fashion of Han. Compared with the Zhejiang School and the Deng School, however, the influence of the Fujian School on the art of seal cutting is not very great or noticeable. They were later absorbed either by the Zhejiang School or the Deng School.
After the Eight Great Seal Artists of Hangzhou, the tradition of the Zhejiang School was carried on by such famous artists as Zhao Zhiqian (趙之謙, 1829-1884) and Wu Changshi 吳昌碩. Wu died only about a decade ago, and was the first president of the West Lake Seal Society at Hangzhou. Meanwhile, the Deng School had fallen apart since the passing of Wu Tingyang with the result that nearly all the living seal artists now, such as Wang Shi 王禔, Tang Yuanye 唐源鄴, Ye Weiming 葉為銘, and many others, are members of this Zhejiang School. And it was these men who founded the West Lake Seal Society to perpetuate the art of seal cutting.
So much for a brief historical resume. Let us now enquire into the aesthestic aspect of the art of Chinese seal cutting. In the first place, what distinguished artistic seals from those which are not, i.e., seals cut by professional seal cutters instead of by scholars, lies in the use of the style or script of characters on the seals. For, on Chinese seals we do not find characters in the modern style of writing, but only characters in various old script forms. According to Zhuanke Zhendu 篆刻針度, eight kinds of scripts are used in Chinese seal cutting. They are: dazhuan 大篆, xiaozhuan 小篆; kefu 刻符; chongshu 蟲書; moyin 摹印; zhushu 著書, shushu 殳書; and, lishu 隸書. Besides these eight kinds, the script found in Chinese bronze inscriptions is also sometimes used. Thus, a Chinese seal artist must be a good authority on etymology. It is for this reason that only scholars can appreciate the art of seal cutting: it is only scholars who can at the same time be good seal artists. The Eight Great Seal Artists of Hangzhou are all scholars of note. Besides being famous for their art of seal cutting, they are also well-known for their calligraphy, painting, and scholarship in archaeological research. Even such living seal artists as Wang Shi, Tang Yuanye, and Ye Weiming are known for their calligraphy and their knowledge of the Chinese bronze and stone monuments.
As in the case of Chinese calligraphy, the art of 'Iron Pen' also lays equal emphasis on the composition of each individual character on the seal as well as the composition of the group of characters taken as a whole. But a well-balanced composition alone is not enough. A good seal must not only be well-balanced but must also embody what is known as daofa 刀法, that is the way the scalpel is handled while cutting. There are several ways of handling the scalpel, such as, for instance, Double Cutting 複刀, Reverse Cutting 反刀, Flying Cutting 飛刀, and so on. These different ways of handling the scalpel must be shown on the characters cut on the surface, failing which the seal cannot be considered a good one.
According to Moyin Chuandeng 摹印傳鐙, there are Six Laws 六法, Six Essentials 六要, Six Merits 六長, and Three Categories 三品 in the art of seal cutting.
The Six Laws are:
1. There should be a liveliness of manner in the way the seal is cut 氣運生動; 2. The traditional ways of handling the scalpel must be adhered to 刀法古勁; 3. The composition must be well-balanced 布置停勻; 4. When writing the characters in old script on the surface of the seal before cutting, the authenticity of the characters must be carefully scrutinized and the scholarly way of writing them adhered to 篆法大雅; 5. The cutting must strictly follow what is written by pen on the surface of the seal 筆與刀合; and, 6. A seal artist must not allow himself to sink to the level of mere professionals 不流俗套.
Among these Six Laws of seal cutting, the author states that it is most difficult to attain to the state mentioned in the First Law, that is the display of a lively spirit in the way the seal is cut.
As to the Six Essentials, they are:
The Six Merits of seal cutting are:
The Three Categories are: the Divine 神品, the Exquisite 妙品 and the Competent 能品. According to Ye Erkuan 葉爾寬, author of Moyin Chuandeng, that which has attained to a state of natural liveliness of manner may be said to belong to the first category, i.e., the Divine; that which has attained to a state of fineness in penmanship, and which appears to be very clumsy and yet very lively may be called the Exquisite; and that which has attained to a state in which the old ways of cutting are strictly adhered to may be called the Competent. All other critics agree that there are these three categories; but as to what they denote, they are at variance.
Chinese seals are usually cut in two ways: one is known as yangwen 陽文, i.e., characters cut in relief, and the other is called yinwen 陰文, i.e., characters made by incision. Both have their merits, though yinwen is a much older style of cutting. For in the Han dynasty, no seal was carved in relief. They were either moulded or incised. It was only after the collapse of the Han dynasty that yangwen came into vogue. Since then it has been the usual practice for seals on which one's official name appears to be cut in incision, and those on which one's literary name appears to be cut in relief, that is yangwen. Traditionally, the seal on which one's literary name appears was considered inappropriate if one's surname also appears on it, while in the case of the seal on which one's official name appears, one's surname must be added. This practice, however, is not now generally observed.
Fig.4 Seals cut by two living artists: Wang Shi 王禔 and Ye Weiming 葉為銘
Besides the cutting on the surface of a seal, good seals must also have inscriptions cut on the side. No good seals are considered complete without the side inscriptions 邊款. The side inscriptions usually give the name of the artist who cut the seal and the name of the owner of the seal. In addition to these, lengthy inscriptions are also sometimes found. There are certain orthodox and traditional ways of cutting the side inscriptions, which are quite different from the ways of cutting the surface. In the first place, before cutting the surface, the characters must first of all be written on it, while in cutting the side inscriptions no such procedure is necessary. One cuts directly on the side of a seal without having to have the characters first written on it. The scalpel is wielded like a pen or a brush, hence the name, the art of Iron Pen. A connoisseur of the art can even distinguish after what old master the style of the side inscriptions is. For instance, the side inscriptions of Chen Hongshou are quite different from those cut by Ding Jing, Zhao Zhiqian, and others.
As to the materials for seal making, there are many. Jade was reserved only for the seals of the emperor. However, with the fall of the Ch'ing dynasty, no such restriction was observed. Stone is the most common material for making a seal, though its use began as late as the Sung dynasty. There are various kinds of stones, the most common being Qingtian Shi 青田石 from the district of Qingtian in Zhejiang province. Others are Shou Shan Shi 壽山石 from the province of Fukien, of which there are several varieties, such as Tianhuang 田黃, Tianlan Dong 田藍凍, Furong 芙蓉, and many others. Chu Shi 楚石 from the province of Hunan, and Changhua Shi 昌化石 from the district of Changhua in Zhejiang province are also used. Among these various kinds of stones, Shou Shan Shi, particularly that variety known as Tianhuang, is most treasured by the lovers of Chinese seals. Shou Shan is located some eighty li north of the city of Fuzhou. The stones there were first quarried in the Song dynasty. During the reign of Kangxi in the Qing dynasty, a man named Chen Yueshan 陳越山 formed a company to work on this quarry, with the result that its best product soon became exhausted.
The stones suitable for making seals are what is known as soapstones or steatites. But not all soapstones are suitable for seal cutting, for if it is too soft, then the seal will not last long. So only those stones which have, as it were, a sort of hardness in softness can be used for making seals. It is for this reason that Shou Shan Shi and Qingtian Shi are best suited for seal cutting.
Besides the various kinds of stones, other materials used for making seals are: ivory, bronze, gold, silver, crystal, a kind of special wood known as Huang Yang 黃楊, the root of old plum trees and bamboos, the last two being very seldom used.
Outside China, the art of seal cutting is also developed in Japan. Japan has produced several seal artists of note who can bear comparison with the best Chinese seal artists. In the Guang Yinren Zhuan 廣印人傳, there are listed the names of sixty-three Japanese seal artists, some of whom visited China as late as the second decade of the present century, and became foreign members of the West Lake Seal Society. They are, among others: Senro Kawai 河井仙郎, Kinoe Nagao 長尾甲, and Tetsujo Kuwana 桑名鐵城. A native of Takamatsu, Nagao came to China in the early years of the Republic, and soon won the friendship of Chinese literati. On the rocks in the West Lake Seal Society there is still an inscription cut after his writing. Besides being a good seal artist and calligraphist, Nagao is also a good painter of Chinese landscape. As a poet writing in the Chinese style, Nagao has collected his poems into a volume entitled Heyuan Lou Shigao 何遠樓詩稿; as a Chinese scholar, he has written two treatises on the development of Chinese poetry and on Confucianism entitled Gujin Shibian 古今詩變 and Ruxue Benlun 儒學本論.
No less a Chinese scholar is Kuwana. He visited China twice in the later years of the Qing dynasty. He had a rich collection of Qin and Han seals and had published many volumes on the art of Chinese seal cutting, such as Tianxiang Ge Yinpu 天香閣印譜, Jiuhua Tang Yincun 九華堂印存, and others. Kawai, a native of Kyoto, is also a good Chinese scholar. He was in China several times and became a good friend of the late Wu Changshi, who is perhaps the last of the great Chinese seal artists.
Related material from China Heritage Quarterly:
 See Yunzhuang Yinhua 雲莊印話 by Ruan Chong 阮充.
 See Yin Dian 印典 by Zhu Xiangxian 朱象賢.
 See Yin Dian.
 See Jinshu Zhiguan Zhi 晉書職官志.
 For a discussion of the various rules of shou and niu, see Yin Dian.
 See Handai Xueshu Shilüe 漢代學術史略 by Gu Jiegang 顧頡剛.
 Yin Tan 印談 by Shen Ye 沈野, see also Yin Dian.
 See Zhuanke zhendu 篆刻針度 by Chen Keshu 陳克恕.
 For a further discussion on these three categories, see Zhuanke zhendu, Yin Tan, Yunzhuang Yinhua, etc.
 Remains of stone seals were discovered by Stein at Loulan. See John C. Ferguson, Survey of Chinese Art, p.129.