I. Introduction
Seal plays a crucial role and represents a trust of credit and commitment in Chinese world, no matter in daily life, in society, in the past, and at present. Request for seal and signature will be occurring in various situations, regardless of official or private occasions. Seal is also used by Chinese calligrapher and painter while conducting their artworks. Signature and seal of the artist on a painting is the way of showing recognition and uniqueness. Hence, these marks on painting are essential evidences for distinguishing genuine works.
II. History of seal
A. Origin
Seal was called “Imperial Seal” (Xi) in ancient China and its origin is considered to start in Neolithic age by archaeologists, who discover that seal developed from imprinted decoration on potteries. In 1930, Mr. Huang bin-hong listed many instances of pottery script consistent with antique seal in his published book, “Proof of Words on Pottery and Seal”. He proved that seal was used for name sign on pottery and found that decoration marks by imprinted mold appeared on earliest pottery. As well, Mr. Na Zhi-liang stated two kinds of decorations on pottery in his book “General Definition of Seal” in 1970. He mentioned that one decoration is applied tapping method, and the other is imprinted decoration made by pottery mold or stone mold. Later, the decoration mold advanced to mold carved with words, and the mold gradually become Seal (Pottery seal).
Imprinting mold spread from Neolithic age to Warring States Period (475–221 B.C.). At that time, some of the molds were applied by pottery maker, and some became implements of power and trust. During Spring and Autumn Period (722 - 476B.C.) and Warring States Period (475–221 B.C.), unrest politics and growing economy fostered seal development from official representation to civil implement among trust documentation.
B. Appellation and characteristic
Seal had different appellation in different dynasties. In Shang dynasty (1600-1066 B.C.) or before Qin dynasty (221-206 B.C.), seal was called “Ancient Shu” or “Shu”. After that, “Xi” (Imperial Seal) was named, and changed to “Yin” or “Zhang” in the reign of Wu emperor in Han dynasty (206 B.C. – 220 A.D.). When time shifted to Tang dynasty, Wu empress called Seal “Bao” (treasure). Alias of seal was added like “Ji” or “Zhu Ji” after Southern and Northern dynasties (420-581). When stepping into Song dynasty (960-1279), “Tu Shu” became new name of seal due to mistaken alias through tradition.
Seal in Yuan dynasty (1279-1368) was similar to signature in modern days. “Yuan-Ya” was signature in seal form, which was carved with last name on top and flower signature (distinct picture) on seal bottom in rectangle shape of seal. Furthermore, official seal of Ming dynasty (1368-1644) was named “Yin” in square shape, and named “Guan Fang” or “Tiao Ji” in rectangle shape. In Qing dynasty (1644-1911), seal had various names, such as “Chuo Ji”, “Chou Zi”, and “Shou Chou”. Afterward, official seal was called “Yin” or “Zhang” and private seal was called “Si Ji”, “Tu Shu”, and “Tu Zhang” on account of distinguishing differences.
However, Seal from different periods carried certain features that included material, shape, size, center of gravity, carving line, carving design of words, frame, and word type. Besides, the seal inscription was mostly related to official title, name, and few propitious blessing before Tang dynasty (618-907). Then, seal gradually developed into two purposes thereafter. One purpose is to carry on practical use of seal, as like official and documentary identification in modern time. The other is art seal that possessed both practical and art value, and developed from “Name of studio” in Tang dynasty.
The prime minister of Tang dynasty (618-907), Li Mi, was the first one had seal inscription in name of his private studio, Duan Ju Shi. Afterward in Song (907-1279) and Yuan (1279-1368) dynasties, seals added content of inscription like alias, storage, poetry, idiom, and so on. Thus, the purpose of seal not only expanded in practical use but raised artistic value for appreciation and collection.
III. Character arrayal of seal
“Zhangfa” is the word arrayal of seal and its importance is like design chart of architecture. Owing to the difference in structure of seal characters, the character arrayal carried various artful changes that are divided into twelve kinds as follows. (Figures as reference)
A. Position Density: Each Chinese character occupies same measure of area on seal bottom no matter with simple or multiple strokes. For this reason, alternate methods are applied to perform well-balanced position density. For instance, natural spacing method is consisted of dense character with multiple strokes and thin character with simple strokes. Another is to apply complementary method that is composed of slim multiple strokes and stout simple strokes. Natural and perfect position density is seen on square seal with incision of “Tao Lu You Hao Chi Zhai” by Wang, bing-tie.
B. Carving Strength: Carving strength differs while writing seal characters, carving and molding artworks. Some natural situations happened occasionally, such as thin stroke made by quick cool down on outline while molding process or abrasion on seal with wide characters and thin frame. Thus, balance of carving strength on seal characters forms aroma of heavy left with light right or heavy top with light bottom. Giving an example of boxy seal with incision of “Dong Ling Qiao Ren” by Qi, Bai-shi, it presents natural taste in virtue of word type with vertical strokes in needle end (heavy top and light bottom).
C. Stroke Variation: In order to harmonize seal characters on seal bottom, simple or multiple strokes of seal character are added more or less strokes flexibly on account of rules of character formation, evolution of calligraphy, and etc. Four seal characters with three multiple strokes and one simple stroke vary to total four characters with multiple strokes. On the other hand, four seal characters have three characters with simple strokes and one character with multiple strokes that is simplified. Square seal bottom with carving of “Hui Shu Shou Jiao” by Zhao, Zhi-qian possessed two characters with multiple strokes and the other two with simple strokes. Balance of characters on seal bottom is achieved by simplifying “Shu”.
D. Shape Alteration: Seal character alter its shape on the basis of character stroke most in round shape. After Qin dynasty (221-206 B.C.), there was a trend that prolonging down stroke of seal character. Great seal character is consisted of applying decent shape alteration and standard writing rules. The rectangle seal bottom with incision of “Zhu Shan” (Bamboo Mountain) by Wu, Chan-Shuo harmonized spacing by prolonging “Zhu” for matching with short “Shan”.
E. Structure Correspondence: Each seal bottom needs to pay attention on structure correspondence of seal character, whose harmony is affected by character’s shape, size, and number of strokes. Citing an instance on square seal bottom with incision of “Dao Zai Wa Pi” by Zhao, Gu-ni, impression of structure correspondence was formed by two characters with multiple strokes (Dao, Pi) and two characters with simple strokes (Zai, Wa) in cross corner. “Zai” was carved as “Cai” because both characters are the same word in ancient seal character.
F. Size Proportion: Seal character has features of multiple strokes, simple strokes, and changeable shape, therefore balance of seal bottom is achieved by adjusting size and position of seal characters. The boxy seal bottom with incision of “Wu Xi Zai Yin” by Wu, Rang-zhi presents proportioned size of seal characters by enlarging two characters with multiple strokes (Xi, Zai).
G. Interlaced Arrangement: Interlaced arrangement is to blend characters together and demonstrate natural vividness. There is an ancient seal (Gu Ni) with two characters (Shou Jing) on round seal bottom. “Shou” is located in right top corner and possesses fourth area of whole seal bottom. On the other hand, “Jing” occupies three-fourths area of whole seal bottom and its entire stokes are scattered around “Shou”.
H. Character Variation: When same character appeared repeatedly in seal inscription, seal character will change its shape to perform artistic style. Seal bottom with incision of “Wo Zhi Wei Wo, Zi You Wo Zai” by Feng, Kang-hou shows cheery aroma in virtue of three “Wo” character in different shapes.
I. Alternative Incision: According to character’s attribute or its incision, irrelevant characters are linked together by alternative incision which means seal inscription is carved both in intaglio and in relief (common in seals of Han dynasty – 206. B.C - 220 A.D.). There is an instance from seal in Han dynasty with incision of “Yang Du”. “Yang” on the right was carved in relief (Zhuwen: red character), and “Du” on the left was carved in intaglio (Baiwen: white character).
J. Skillful Carving: Great seal carvers combine skill of writing and carving to perform marvelous impression, regardless of clever or simple artworks. Rectangle seal bottom with incision of “Tian Ya Yi Ti Yi Shen Yao” by Deng, San-mu presents both skillful carving of strokes and dividing line at the same time. Radical on right side of “Ya” and “Yi” characters are carved as center line.
K. Partition Line: Some seal characters do not match properly, so partition line helps portioning out space for each character, just like red grid in calligraphy practicing for orderly writing. Inscription of “Zhen An” by Wu, Chang-shuo shows appropriate use of partition line, which matches two irrelevant characters in a harmony.
L. Stylish Border: The bouquet of a seal relates with seal inscription and seal border. Orderly seal inscription goes with orderly border, and irregular seal inscription goes with irregular border. The seal border was carved irregularly in tone with seal characters by instantiating inscription of “Yan Tian Wu E Sui” by Wang, Fu-Han.
Figure：Twelve kinds of seal bottom in terms of character arrayal
1. Position Density
2. Carving Strength
3. Stroke Variation
4. Shape Alteration
5. Structure Correspondence
6. Size Proportion
7. Interlaced Arrangement
8. Character Variation
9. Alternative Incision
10. Skillful Carving
11. Partition Line
12. Stylish Border
Figures of seal mark derive from Art of Seal Carving by Wang, Bei-yue, p.39-41.
IV. Carving tools and carving skill
Seal characters (Zhuan word) were the common word type of seal in view of line structure. It has features of orderly even strokes, symmetrical structure, and changeable shape. Various impression and conception are created through artistic word patterns by skillful carving.
In addition, ordinary carving knife of seal has a flat blade with two sides of sharp edges, which are raked about 20 to 30 degrees. Wide edge is half centimeter and narrow edge is two millimeter in length. Sharp and thin blade is put to use for detailed carving, and bold carving applies thick and blunt blade.
Blade of carving knife is divided into flat edge for stone carving and oblique edge for carving bamboo or wood. Furthermore, there are two ways of carving methods, such as upright cutting and side cutting. Upright cutting is to use cutting edge straightly. Eighty percent of cutting edge is used for incising stone while leaning knife tool within ten degrees aside vertical. When incising with strength, cutting edge is focused on the center of strokes and shapes irregular sides of stroke owing to extrusion of side edge. The other cutting skill is side cutting which is using side edge for cutting. The cutting edge is held at an angle of fifteen degrees from stone surface and only one side of edge is used while carving. In this case, carved stroke is smooth on one side and irregular on the other side. Thus, upright cutting shapes thinner strokes and side cutting shapes wider strokes. However, stone seal has common size in square of 2 to 9 cm2, so side cutting is mostly used for stone seal carving.
Besides, the ancients often used double hooking of knife holding method which was treated as the only one method of knife holding. Nevertheless, knife holding methods were applied and varied by seal carver in basis of different artworks. There are three kinds of knife holding methods, comprising clenching method, dragging method, and pushing method. When carving large seal, clenching method is put to use. For instance, Mr. Qi Bai-shi applies this method while carving. Pushing method is suitable for carving small seal but the variation of skills depends on personal habits.
After all, there are two ways of using knife. One is called rushing knife, which incises smooth lines and applies upright cutting or side cutting. The other way of using knife is chopping knife that performs flat deep stroke. The chopping knife is to cut deep and forward along with pressing strength, and each cut is about half length of cutting edge. The stroke is completed by several cuts in a row. For instance, Mr. Wu Chang-shuo usually uses rushing knife method to display broadness. Mr. Xu San-gen habitually applies chopping knife method to demonstrate uniform style. Both of them are good at using knife skills. More to say, the way of carving Zhu Wen (red Characters) is usually done by two cuts in one stroke and in opposite direction. However, there is exception that Qi Bai-shi carves Zhu Wen in same direction. While carving Bai Wen (white Characters), one cut in one stroke is called “Single cut” and carving in same direction is called “Double cut”. Besides, Zhu Wen is carved along outline of seal characters and raise embossment of characters. On the other hand, Bai Wen is incised along inner of seal character and become intaglio characters.
Seal carving is the art combines calligraphy and carving skill. In short, there are many ways of using carving tools, but all the methods depend on maturity of personal skill to create special and excellent taste.
V. Seal material and seal paste
Material of seal mainly used gold, silver, copper, and metal materials in early period. Later on, various materials were applied in sort of animal material (rhino horn and ivory), mineral material (jade and semiprecious stones), plant material (bamboo and wood), and artificial material (plastic). Among all the materials, firm seals like copper and jade had been prevailed for long in history of seal development. Wang Mian of late Yuan dynasty combined writing and carving together in material of Hua-lu stone and first demonstrated personal style in a small stone seal area. Since then, seal of personal use chooses material of soft stone that becomes main material of seal carving.
Stone material for carving not only expresses knife skills but possesses a quality that is easy for incising and has hardness between 2.5 and 3 degrees. Above all, Shoushan stone, Blue-field stone, and Changhua stone maintain the best quality and great reputation.
The most high-class stone material for seal is the mildly moist Shoushan stone from Fujian province. It can be divided into three ways of production, including field-pit stone, water-pit stone, and mountain-pit stone. The first sort has the best in field-yellow stone, and the second sort has the best in steatite that is crystal-clear. The third sort has great material from high mountain steatite and Ducheng or Duling pit. Other advanced stone materials comprise clear blue-field steatite of blue, yellow, and white shades from Zhejiang province, and bright Changhua stone of top chicken blood red.
Moreover, good seal has to be provided with good seal paste. Seal with bad seal paste will put into the shade. The lifespan of seal paste is generally between five to ten years. Good seal paste of over confection lasts the same condition for years of using. After keeping covered in ceramic container, paste still remains unchangeably bright new gloss and steady condition after hundreds of years. Even though it has been used, the seal paste naturally presents a luster that still shines while whisking it off.
The main ingredients of seal paste contain cinnabar, stamp-pad oil, and moxa. There is detailed illustration of ancient production of seal paste in the book of Siku Quanshu (translated as the "Imperial Collection of Four"). It mentioned that seal paste is made by dipping sesame oil with Zhoujiao inside porcelain ware before decocting. After it was cooled down, making an agent with Shouai and adding vermilion. Then, taking the red seal paste in the silk bag and turning it over while staying in porcelain or jade ware (avoiding copper ware or tinwork) for days. If oil dried out afterward, repeatedly using fried oil in a ware and making dry paste absorb voluntarily (No pouring oil from top). This method will keep seal paste getting better even last a long time.
VI. Seal Appraisal
General appraisal on renowned painting or artwork included paper era, composition, style, signature mark, and so on. Among them, signature mark contains seal mark comparison whether it is corresponding to personal seal of the artist or not. This job seems like simple but it has certain difficulties because each artist owns various seals in numbers of ten to hundreds.
DCL-CARD will illustrate brief procedure of seal mark comparison via painting of Fu Bao-shi as bellows. At first, setting up files of signature mark and seal mark shown on the painting of Fu Bao-shi. After that, searching similar seal mark record in the book “Seal Mark Collection of Modern Artist”. Then, scan system is applied to produce overprint of seal mark and digital file. Last, meticulously check and confirm the comparison of seal mark.
Painting by Fu Bao-shi from collection of DCL-CARD
Signature mark and seal mark on left right corner of painting by Fu Bao-shi
Seal mark record from the book“Seal Mark Collection of Modern Artist, part II”
Overprint of seal mark from seal mark database
VII. Reference
1. Zhang, Fu-jiang. Si Ku Quan Shu Complete Library in Four Branches of Literature, Beijing: East, Jan. 2004.
2. National Palace Museum. The National Palace Museum Monthly of Chinese Art No.119, Vol. 10, Issue 11. Taipei: National Palace Museum, Feb.1993,
3. Wang, Bei-yue. Art of Seal Carving, Taipei: Han-guang, Jul. 1990.
4. Lu, Fu-sheng. Seal Mark Collection of Modern Artist, part II, Shanghai: Shanghai Painting, Aug. 2004.
5. Chen, Xi-ming et al. Appreciation of Shoushan Stone, Taipei: Hua-Sheng-cheng international art, Nov. 1985.
6. Zhang, Jun-Xun. Investigation of Shoushan Stone, Taipei: Art Book, Apr. 2002.
7. Wang, Jing-zhi. Tian-huang Stone Appraisal, Taipei: Nation, May 2004.
8. Fang, Zong-gui. Shoushan Stone Appraisal, Taipei: Nan-tian, Apr. 1995.
9. Feng, Zuo-min. Record of Chinese Seal, Taipei: Art book, Oct. 1993.
