Analysis for Conservation of the Timber-Framed Architectural Heritage in China and Japan from the Viewpoint of Authenticity

Abstract

The precious timber-framed buildings of both China and Japan have been preserved as heritage. Over time, the conservation and restoration of heritage in both countries have gradually matured. The restoration projects in each country are mostly guided by the documents promulgated by ICOMOS, which are followed as closely as possible in the actual restoration process. Nevertheless, the specific restoration projects in the two countries show a difference in their perceptions of authenticity, especially at the practical level. Therefore, this study intends to improve our understanding of the “authenticity” in the restoration projects of China and Japan so as to provide better guidance for practice. Therefore, this study firstly reviews the development of the conservation theory of authenticity in the West and East Asia. We then analyze the recent restoration projects of three typical study objects from China and Japan—Nanchan Temple, Foguang Temple and Toshodai Temple, which are all world cultural heritage sites—and conduct a comparison study to analyze the embodiment of the concept of authenticity in the actual intervention process. Accordingly, based on the analysis of comparative cases and documents, combined with the statistical results of the frequency of “authenticity” and “intervention” being mentioned in the international documents, we provide insights into the theories of heritage conservation in China and Japan.

1. Introduction

1.1. Background

Authenticity is an important concept that originated in Europe in the field of heritage conservation and was first developed for the protection of works of art. The development of European art history and the collection and conservation of works of art in the 18th and 19th centuries, in particular, gradually led to a discussion and understanding of authenticity [1]. In the field of contemporary cultural heritage, it is generally accepted that a sense of conservation of authenticity was first reflected in the Venice Charter. This was followed by the 1977 Operational Guidelines for the Implementation of the World Cultural and Natural Heritage, which proposed authenticity as a test of cultural heritage [2], and the 1994 Nara Document on Authenticity, which expanded the meaning of authenticity based on cultural relativism. Following the adoption of the Nara Document, a major international debate on authenticity began, and research began in the domestic academic community [3]. The Operational Guidelines of the World Heritage Convention and the Nara Document are the most important documents on authenticity followed at the international level, specifically in terms of the sources of information needed to judge authenticity, which are the following: form and design, material and substance, use and function, tradition and technology, place and context, spirituality and emotion, and other intrinsic or extrinsic factors. The use of these sources allows for a detailed examination of the specific artistic, historical, social and scientific dimensions of cultural heritage. In recent years, authenticity has begun to encompass a non-material dimension. In 1995, ICCROM President Paul Philippot argued that authenticity is a measure of the intrinsic unity of the creative process, of the material achievement of the work, and of its “authenticity” as it has been affected by the passage of time, in terms of the creative process and time. In 1995, Yohga Yogileto published a paper in which his views, as Director of the Architecture Department of the International Centre for the Preservation of Cultural Heritage under the United Nations, represented the mainstream of international scholarly understanding. He argued that authenticity is the degree to which the process of creation of a work and its material realization are intrinsically united to achieve authenticity, and the degree to which it has been stripped away through the ages. In 1997, a Finnish scholar suggested that buildings are most authentic when they are given their original atmosphere, and that authenticity is a certain constant in buildings. The 2005 Operational Guidelines for the Implementation of the World Heritage Convention incorporated the Nara Document’s interpretation of authenticity and confirmed the Nara Document’s importance as a basis for assessing the authenticity of heritage—an operational basis—and as of 2017, the latest version of the Operational Guidelines for the Implementation of Safeguarding World Cultural and Natural Heritage of the World Heritage Convention remains unchanged with regard to authenticity [1].

In 1964, the Venice Charter was issued, referring to the principles that should be followed when restoring heritage objects and stressing that the restoration process is a highly professional exercise whose aim is to preserve and present the aesthetic and historical value of the monuments. This charter emphasized our duty to preserve heritage items along with the full richness of their authenticity [4]. In 1972, the General Conference of the United Nations Educational, Scientific and Cultural Organization issued the Convention Concerning the Protection of the World Cultural and Natural Heritage, which defined cultural heritage and highlighted its universal value [5]. In 1977, in the Operational Guidelines for the Implementation of the World Heritage Convention, authenticity was introduced as a fundamental inscription indicator for World Heritage. The following ideas regarding authenticity were presented. Cultural heritage should be tested for authenticity in the following areas: design, materials, workmanship and environment [2]. In 1990, a Charter for the Protection and Management of Archaeological Heritage was issued, reflecting basic principles and guidelines that are common worldwide, thus making it unable to cover specific issues of a geographical or national nature, as well as their various potentialities [6]. In 1994, the experts of the Nara Conference in Japan presented the Nara Document on Authenticity, which aimed to verify authenticity in a way that respects all social and cultural values and to test the universal value of cultural assets inscribed as World Heritage [3]. In 1999, ICOMOS Australia issued the Burra Charter, which defined important terms in the process of heritage conservation [7]. In 1999, at the ICOMOS Mexico Congress, the guidelines for the Principles for the Preservation of Historic Timber Structures were adopted, with the aim of preserving and perpetuating the historical authenticity and integrity of cultural heritage. The guidelines proposed interventions, based on proper research and evaluation, that respect the aesthetic and historical value and integrity of historic monuments, while emphasizing that the least possible amount of intervention is the most desirable approach to the conservation of the historic remains of timber structures [8]. In 1999, the Charter on the Built Vernacular Heritage was published, suggesting that vernacular architectural heritage is of great importance as a fundamental expression of the relationship between the culture of a group and the land [9]. In 2003, Principles for the Analysis, Conservation and Structural Restoration of Architectural Heritage were published, with the aim of contributing solutions to the conservation and restoration problems. It also emphasized that the value of architectural heritage lies not only in its appearance, but also in the way in which its parts form a whole that reflects the specific construction techniques of the historical period in which it was built, and that complete removal of the interior structure, leaving only the exterior of the building, is incompatible with conservation standards [10]. In 2007, the Beijing Document—International Symposium on the Concepts and Practices of Conservation and Restoration of Historic Buildings in East Asia was adopted in Beijing to address the concerns raised by the 30th General Assembly of the World Heritage Committee regarding the ongoing restoration of the Forbidden City, the Temple of Heaven and the Summer Palace in Beijing. The document emphasized the need to implement authenticity in practice, with particular attention paid to paragraphs 9 and 13 of the Nara Document on Authenticity [11].

1.2. Literature Review

In recent years, there has been an increasing amount of literature exploring the authenticity of heritage. From the analysis of seismicity and built heritage in Japan and Colombia, Niglio et al. [12] presented the first results of a piece of comparative research between the two countries, and the different methods of intervention and management used to protect the architectural heritage, which are important to reduce their vulnerability. Sakayama [13] discussed the evolution of the conservation system of heritage buildings in Japan, illustrating the Japanese principle of “restoring the old as the old” with numerous examples and comparing it with the conservation principles of heritage buildings in China. Chang [14] showed that originality is not simply the same as authenticity, nor is it original; rather, it is a different superimposition of architectural heritage within the historical period of its existence. Lu [15] outlined the origins and twists and turns of “authenticity”, but did not offer a precise meaning of “authenticity”, and pointed out that there is no ideal conservation code that applies to all architectural heritage, and what is preserved and what is abandoned should be made clear in the practice of architectural heritage conservation, where choice means abandonment. Zou [16] analyzed the principles of authenticity in the East and West, and proposed that the Eastern principle of authenticity is based on the traditional concept of not making essential distinctions between originals and reproductions, replacing components and materials, and maintaining the continuity of wholeness and traditional craftsmanship. Lv [17,18,19] compared the formation and development of Liang Sicheng’s concepts on the conservation of heritage buildings, examining his ideas on the development of Chinese heritage architecture conservation theory, and also provided a systematic discussion of the concept of conservation, perception of value, emergence and development of conservation principles, and the impact of the Venice Charter on the conservation of heritage buildings in China, providing an in-depth study of the value of heritage buildings and the development of their restoration and conservation principles. Chen [20] translated and introduced a range of international conventions and documents on the conservation of heritage buildings, examining documents on the significance and implications of the conservation of heritage buildings in China. Zhu [21] analyzed how the Chinese government imposes the concept of authenticity on local heritage practices in the process of heritage nomination, conservation and management. Li [22] et al. presented the technical route of monitoring the Foguang Temple under the concept of preventive conservation, and the results of analysis of some monitoring data. Steinhardt [23] discussed how the modern study of Chinese architecture was initiated by Liang Sicheng in the 1930s. Today, Liang’s ideas dominate the field, particularly in terms of their influence on the study of Chinese Tang architecture. Liu [24] et al. analyzed the wooden structure system of the Baoguo Temple and compared it with the halls of Buddhist temples of other dynasties, presenting the evolution of the wooden structure system of Buddhist architecture. Henrichsen Christoph [25] investigated how Japan, which ratified the World Heritage Convention in 1992, fulfils these requirements. It also proposed parameters to determine the authenticity of a particular architectural monument and applied them to current monument conservation efforts in Japan. Zhou [26] et al. compared the differences between Chinese and Japanese traditional wooden building techniques and analyzed the reasons for the differences between Chinese and Japanese traditional wooden buildings from the perspective of the natural environment and building techniques.

Among the traditional building systems of the world, the architecture of East Asia is dominated by timber-framed buildings, with Chinese and Japanese timber-framed buildings being the earliest and most mature, and having a profound influence. The unique construction techniques of traditional timber construction, with timber as the main building material, mortise–tenon as the main method of joining timber elements, and modal design and production scale standards, are the unique value of Chinese and Japanese architectural heritage. The architectural monuments that have survived to this day are a testimony to history [27]. Wooden architecture in China and Japan is an important part of the precious cultural heritage of both countries shared by mankind.

As a result of the above discussion, it is clear from the literature and the enactments that the search for “authenticity” has evolved. In the field of heritage conservation around the world, “authenticity” is an important indicator in the evaluation of heritage, and in Asia and East Asia, “authenticity” is an important guideline to be applied in the restoration of recent heritage. Thus, the Nanchan Temple and the Foguang Temple in China, and the Toshodai Temple in Japan, which are highly controversial in academic circles, have been selected as representative and typical of the buildings that have been registered as World Heritage Sites in China and Japan. Therefore, this study investigates the extent to which ICOMOS documents have been implemented in the restoration of Chinese and Japanese heritage in recent years, and to compare the similarities and differences in the restoration concepts of the two countries, taking into account the structural characteristics of the heritage and restoration of timber-framed buildings in both countries. It further explores the “authenticity” and “human intervention” of heritage conservation. In addition, the conclusion discusses the current state of heritage conservation in China and Japan and makes constructive suggestions for the future of heritage conservation in both countries.

2. Methodology

This study mainly used case studies with comparative and statistical methods as follows (Figure 1).

The first step of the study was to collect examples of heritage restoration in China and Japan during recent years. By summarizing the documents promulgated by ICOMOS, and based on the documents promulgated by ICOMOS at the time, as well as further taking into account the conservation regulations enacted by each country, the study analyses whether the restoration considered the authenticity of the heritage, and whether the restoration was carried out with the least possible human intervention. In addition, we compared and summarized the similarities and differences in the restoration of heritage in the two countries and explain the reasons for these.

The second step was to compile a statistical summary of the concepts of “authenticity” and ”intervention” in the heritage regulations issued by China and Japan, and to compare the differences between the two countries, as well as the frequency of mentions of authenticity and intervention in the ICOMOS documents, especially with regard to the conservation of heritage buildings and the principles of material use.

3. Case Studies

This section focuses on the collection of Chinese and Japanese heritage conservation documents, as well as statistics and the extraction of important key words, such as “authenticity”, “intervention” and structural repair, from the documents issued by ICOMOS. The case studies are derived from China and Japan: one from the Tang Dynasty for the main hall of Nanchan Temple, and the other for the east main hall of Foguang Temple, which was registered as a World Heritage Site in 2009 [28]. The other object of study was the Toshodai Temple.

3.1. The Regulations of Conservation of Cultural Property in China and Japan

The conservation of Chinese cultural heritage in the modern sense lags behind the West in terms of its emergence. Its emergence and development was both a conscious act under the continuation of tradition and inseparable from external influences, especially Western discourse [29] (

Table 1. Major heritage conservation regulations in China *.

Year	Regulations Issued
1906	The measures for the promotion of the preservation of antiquities were formulated, and all provinces were ordered to implement them.
1928	The government of the Republic of China established the Central Commission for the Preservation of Antiquities and, in the same year, the Ministry of Internal Affairs issued the Regulations on the Preservation of Places of Interest and Antiquities.
1930	Conservation of antiquities.
1931	Antiquities Preservation Act Enforcement Regulations.
1961	The State Council promulgated the Interim Regulations on the Protection and Administration of Cultural Relics, Interim Regulations on the Conservation and Management of Cultural Heritage.
1982	Law of the People’s Republic of China on the Protection of Cultural Relics.
2000	Guidelines for the Conservation of Cultural Heritage Sites in China.
2015	Guidelines for the Conservation of Cultural Heritage Sites in China (Revised Edition).

* Source from references: [13,29].

).

Japan’s cultural heritage is under the jurisdiction of the Ministry of Education, Culture, Sports, Science and Technology and the Agency for Cultural Affairs. The prototype of the system was created in the Meiji era [13], and the documents were then supplemented and perfected. It can be seen that both China and Japan began to formulate relevant documents for heritage protection around the 19th century. They started at almost the same time, and the protection documents were revised and promulgated afterward. It can be seen that the process of heritage protection developed from being non-existent to gradual improvements with the further exploration of, and improvement in, protection concepts and awareness. In recent years, the protection of heritage in China and Japan has been developing and progressing, but there are still differences in the protection and maintenance of architectural heritage (

Table 2. Major heritage conservation regulations in Japan *.

Year	Regulations Issued
1871	The Preservation of Ancient Articles and Antiquities Law, the first preservation regulations in Japan, are issued.
1897	Ancient Temples Preservation Act released.
1929	National Treasure Preservation Act released.
1950	Law on the Protection of Cultural Property released.
1996	The Law on the Protection of Cultural Property is amended to add the registration of tangible cultural property.
2004	Amendment to the Law on the Protection of Cultural Property, addition of cultural landscapes, folklore technology protection system, extension of the registration system.

* Source from reference: [13].

).

3.2. Restoration Cases in China

China has a large number of valuable world heritage sites, but two buildings from the Tang Dynasty were chosen for the study. The main hall of Nanchan Temple is the oldest timber-framed building in China, and its architectural and artistic value represents the characteristics of the Tang Dynasty architecture, which have been restored and preserved to the present day; a compilation of early Chinese heritage restoration concepts were created when it was restored in 1954 and 1974 [30]. The Nanchan Temple is the oldest timber-framed building in China, while the Foguang Temple is the only preserved timber-framed building of the largest volume from the Tang Dynasty. Both buildings are from the Tang Dynasty and have been restored through the dynasties, with some deviations in the authenticity reflected in the architectural heritage, but the architectural heritage can reflect the authenticity of China’s treatment of heritage over the last century, how it has been maintained, the transmission of authenticity, and the changing perception of the issue. The Toshodai temple in Japan is an important ancient building from the Nara period in Japan, built in the same period as the Chinese case, in the same Tang architectural style, but having undergone several large-scale restoration projects. The Japanese perception of authenticity has changed over time. For the above reasons, both are World Heritage sites and belong to the same period, with ancient remains, a timber-framed building, and similar styles; both have undergone numerous restorations, reflecting the changing perception of authenticity in both countries, and are highly typical and comparable as well as being of research significance. Based on the above, the Nanchan Temple and Foguang Temple were chosen as the subjects of the Chinese restoration case study.

3.2.1. The Restoration of the Main Hall of Nanchan Temple

The main hall of Nanchan Temple, the oldest timber-framed building in China (C.E. 782), is an important object in the study of Tang Dynasty architecture. Since its discovery in 1953, its architectural appearance has changed since 1974, when it was dismantled and repaired.

In April 1954, Qi Yingtao submitted a preliminary draft of the restoration plan for the main hall of Nanchan Temple. To be prudent, on 22 July 1954, the Beijing Cultural Relics Committee wanted Liu Dunzhen, Liang Sicheng, Lin Huiyin and Liu Zhiping to send a letter with comments [31]:

Liu Zhiping wrote back on 31 July 1954: “Do not change the status quo lightly without being very sure.”

Liu Dunzhen wrote back on 25 August 1954: “Do more research before making a final decision.”

In 1954 restoration draft, Qi Yingtao advocated the restoration of the Tang style, while Liu Zhiping’s response to the restoration draft was guided by the idea of “conservation of current condition”. It is clear that the ideas put forward by Liu Zhiping coincide with the principle of authenticity in the Nara Document on Authenticity, but the Nara Document was not published until 40 years later [31].

The draft was developed and discussed in 1954, but the repair work was not carried out until 1974. Before the repairs, experts determined after discussion that the windows, doors, arch shapes (Figure 2a), short gable rafters and Zhuru Zhu (Figure 2b) [32] did not belong to the Tang Dynasty style, and that the building should be restored to reflect the Tang Dynasty style. After this restoration in 1974, the exterior was altered. For the windows and doors (Figure 3a), the style was restored to the Tang Dynasty style and the Zhuru Zhu (Figure 3b) were removed. Photos of the Nanchan Temple in its current state and before repairs are shown in Figure 4.

Before its restoration, the Nanchan Temple was reduced in size as its eaves rafters were sawn short, so that its appearance was extremely disproportionate to the ancient structure. In terms of architectural function, the eaves of the building had to be larger than Tai Ming to allow the dripping water from the roof to fall beyond the dormers. As a result, the hall was excavated and cleaned in 1972. The original scale and practice of the Tai Ming was found. It was calculated that the eaves of the Nanchan Temple and the eaves above the center of the gables should be around 230–240 cm. Eventually, the scale and practice of the hall was fully restored in accordance with the excavation, and the two Qing dynasty buildings on which the hall was pressed were removed and not rebuilt [31].

The Wen Shou on the main ridge of the roof is one of the most obvious elements of the tiled roof that expresses the period. According to the documents, the Chi Wei was still mostly used in the early Tang Dynasty, and the image of the Chi Wei, which swallows the ridge with its mouth open, began to appear in the mid-Tang Dynasty. Accordingly, the style of the Chi Wei was still used when the roof was repaired. The choice of the “Chi Wei” in the tilework was also a controversial part of the restoration of the Nanchan Temple. In the 1954 restoration draft, it was proposed that the Chi Wei should still be reasonable, and in 1973, it was proposed that “the specific image should refer to the recent excavation of the Chi Wei of Shangjing of the Bohai Kingdom” (Figure 5a). In August 1973, the 15-member Cultural Heritage Bureau of the Ministry of Culture discussed the program, proposing a reference to the Japanese Toshodai Temple’s Chi Wei (Figure 5b). However, the final use was of Bohai’s Shangjing Chi Wei style [31].

As the restoration plan for the Nanchan Temple is not publicly available, the literature on the restoration plan is cited in Zha Qun’s “A Comparative Study of Two Restoration Plans for the main hall of Nanchan Temple”. The 1974 program proposed that, in the case of restoration based on the preservation of the status quo, the first thing to do was to ensure that the style and scale of the main structure would not be changed.

It is clear from the documentation that the 1954 restoration plan was guided by the idea of “repair to the status quo”, although the specific principles of conservation and the nature of the work were not specified. However, the implementation of the 1974 program on the restoration of the property has a clear proposal: in accordance with the “Interim Regulations on the management of cultural relics” Article 11 “to restore the original state or preserve the status quo” principle, based on field surveys and analysis of the damage, decided to dismantle the overhaul to preserve the status quo mainly, with individual parts restored where there is a sound scientific basis [31].

3.2.2. The Restoration of the East Main Hall of Fogaung Temple

The east main hall of Foguang Temple (C.E. 857) is the oldest surviving timber-framed hall building in China, and is structurally intact and unaltered (the Nanchan Temple is older but, as mentioned in the previous section, has been restored in more recent years). The Foguang Temple, which was built over 1160 years ago, has undergone many repairs in ancient years, but has original internal building components and structures from the Tang Dynasty and a high level of value and authenticity.

In 1937, Liang Sicheng led a survey team from the Society for Research in Chinese architecture to conduct the first mapping survey of the Foguang Temple.

Table 3. Historical research records of the Foguang Temple *.

Year	Affiliations	Main Participants	Results
1937	Society for Research in Chinese architecture	Liang Sicheng, Lin Huiyin, Mo Zongjiang and Ji Yutang	Photographs, mapping, discovery reports.
1951	Yanbei Heritage Study Group	Mo Zongjiang et al.	Information on the Yanbei Heritage Expedition.
1964	State Administration of Cultural Heritage Shanxi Provincial Cultural Heritage Working Committee	Luo Zhewen, Meng Fanxing	A Tang Dynasty wall painting on the girdle of the Buddha’s throne in the center of the door panel was found to be inscribed.
1973	Central and local heritage practitioners	Qi Yingtao, Luo Zhewen et al.	Not available.
2004	Shanxi Institute of Ancient Building Conservation	Qiao Yunfei, Shi Guoliang, Chang Yaping et al.	Photographs, mapping drawings, survey reports, restoration designs.
2005	Taiyuan Huanzhong Geotechnical Survey Co.	Qin Jinsheng et al.	Report on the Geological Survey of the Foguang Temple.
2006	Institute of Architectural Design and Research, Tsinghua University, Institute of Cultural Heritage Protection, Tsinghua Institute of Urban Planning and Design, Beijing	Liu Chang, Wei Qing, Zhang Rong et al.	The Foguang Temple Survey Study Report, The Foguang Temple Conservation Plan.

* Source from references: [28].

shows the activities of the academic survey of the Foguang Temple to date [28].

The elevation and the sections of the east hall of Foguang Temple are shown in Figure 6. Restoration work has not yet been carried out, as Foguang Temple has been well preserved. China’s current conservation philosophy for Foguang Temple is that the restoration of heritage has a huge impact on the “authenticity” and “integrity” of all cultural relics, and that inappropriate repairs can cause irreversible damage to heritage. With the frequent occurrence of natural disasters, especially for such a valuable and important World Heritage Site as the Foguang Temple, the development of restoration strategies must be based on scientific and rigorous research [28].

3.3. Restoration Case in Japan

The Toshodai Temple is the only surviving temple built in the Nara period (late 8th century). It was recognized as a World Heritage Site in 1998. There have been six major repairs in its history. Three dismantling repairs were from the Genroku (1692–1694), Meiji (1898–1899) and Heisei (2000–2009) periods. Three were partial repairs from the late Heian period (first half of the 12th century), the mid-Kamakura period (second half of the 13th century) and the Gensho (1323) period.

It is noteworthy that the major repairs in the Genroku (1692–1694) period changed the gently sloping Tang style roof of the first building, while the Meiji period repairs adopted a king post-truss structure [33].

It is clear from the cross-section of Figure 7 that, at the time of the earliest initial construction, the typical isosceles triangular Cha Shou configuration of the roof and the gentle slope of the roof are very similar to the present structure of the east main hall of Fogaung Temple. However, with subsequent repairs, the structure of the roof gradually added lateral connecting elements, and additional connecting elements between the outer and inner pillars, resulting in a steeper pitch.

Figure 8 mainly represents the longitudinal sections and elevations of the Toshodai Temple from various periods. Figure 8a shows the structure prior to the dateable Meiji repairs, with the patio sections crossed by horizontal and vertical members and no diagonal connections used; however, in Figure 8b, after the Meiji repairs, the roof is extensively constructed in triangles, a complete departure from the original structure. As can be seen from Figure 8c,d, there were changes made before and after the Heisei repair, with the middle five bays on the front of Figure 8c being all windows, while, in Figure 8d, after the Heisei repair, the middlemost window is replaced with five doors, and the size of the windows on either side is enlarged compared to the size before the repair.

Figure 9a shows the Toshodai Temple in its current condition after the Heisei restoration, with the continuous truss structure of the upper part of the patio and the extensive replacement of structural elements. Figure 9b shows the current longitudinal section of the main hall of Fogaung Temple, which retains many of the architectural features of the Tang Dynasty and is similar to the structure of the original Toshodai Temple in Japan, directly reflecting the difference in restoration concepts regarding ancient heritage between China and Japan. It is clear that the early Chinese understanding and exploration of “authenticity” and “minimal human intervention” is highly compatible with the ICOMOS proposal. The middle part of the door of the Toshodai Temple has also changed considerably in size. As can be seen from Figure 10, the width of the current door is narrower than the restored width by approximately 880 cm, while the height of the door differs by 428 cm. Additionally, the size of the windows has also changed and the door shaft in the Genroku period differs from the initial restoration in that it has a different connecting element attached to it (see Figure 11).

During the Meiji period, the Western truss structure (Figure 12) was adopted, and the final Heisei repairs were based on the Meiji repairs, which used truss triangle elements to reinforce the structure and increase its stability [33]. Prior to the Heisei repairs, the columns were leaning inwards (up to 12 cm) and the eaves ends were heavily deformed by sagging due to the roof loads. A reinforcement system was adopted, which was clearly separated from the original frame, and a bracing mechanism was incorporated into the attic to reduce the load eaves, offsetting the horizontal forces on both sides of the building, which caused the building to collapse inwards. In addition, seismic resistance was considered by installing horizontal trusses (Figure 7d and Figure 9a) in the ceiling on the entrance side [33].

4. Results and Discussions

From the above literature review and case studies, the usage of “authenticity” and “interventions” that appear in the documents were summarized by counting the documents that were issued, as shown in

Table 4. Frequency of use of “authenticity” in documents issued *.

No.	Year	Documents Issued	Times
1	1964	The Venice Charter	1
2	1987	The Washington Charter	1
3	1990	Charter for the Protection and Management of the Archaeological Heritage	1
4	1993	Guidelines for Education and Training in the Conservation of Monuments, Ensembles and Sites	1
5	1994	The Nara Document on Authenticity	18
6	1999	Principles for the Preservation of Historic Timber Structures	1
7	2003	Principles for the Analysis, Conservation and Structural Restoration of Architectural Heritage	1
8	2005	Xi’an Declaration on the Conservation of the Setting of Heritage Structures, Sites and Areas	4
9	2007	International Symposiums on the Concepts and Practices of Conservation and Restoration of Historic Buildings in East Asia	8
10	2008	The ICOMOS Charter on Cultural Routes	19
11	2008	Beijing Memorandum on the Conservation of Caihua in East Asia	9

* Source from reference [11], statistics compiled by the authors.

and

Table 5. Frequency of use of “intervention” in documents issued *.

No.	Year	Documents Issued	Times
12	1987	The Washington Charter	2
13	1996	Principles for the Recording of Monuments, Groups of Buildings and Sites	2
14	1999	Principles for the Preservation of Historic Timber Structures	9
15	1999	Charter on the Built Vernacular Heritage	2
16	2003	Principles for the Analysis, Conservation and Structural Restoration of Architectural Heritage	15
17	2008	The ICOMOS Charter on Cultural Routes	5

* Source from reference [11], statistics compiled by the authors.

. The word “authenticity” (Figure 13a) appears 18 times in the 1994 Nara Document on Authenticity, and it appears sporadically in earlier documents. After 2000 it appears most frequently in the 2008 Beijing Document, with 19 mentions. It can be seen that authenticity is gradually being taken seriously as an important indicator of heritage; the frequency of “interventions” (Figure 13b) being mentioned in the documents also shows an increasing trend over the last 25 years, being used 9 times in the 1999 document on Principles for the Analysis, Conservation and Structural Restoration of Architectural Heritage, compared to 15 times in the 2003 document. The emphasis in these documents is on repairing structures with as little human intervention as possible, and using the original components wherever possible.

Two important guidelines for heritage conservation—authenticity and intervention—should be implemented as far as possible in heritage conservation practice, and both the 1994 Nara Document on Authenticity and the 1999 Principles for The Preservation of Historic Timber Structures predate the restoration of the Toshodai Temple. Before that, Japan’s particular geographical location and the frequent occurrence of natural disasters led to frequent repairs to heritage sites that did not follow the recommendations given in these documents. It is worth pondering whether heritage is being preserved or is dying out.

Based on the timing of the enactment of the protection laws in both countries, they both began to be enacted at around the same time. However, in the context of this case study, the development over time and the geographical and natural factors have led to differences in the attitude of the two countries towards the restoration of their heritage when it comes to specific restoration. In the two Chinese cases, various discussions and inquiries can be seen when it comes to heritage restoration. In the case of Nanchan Temple, the internal structure, as well as the external doors and windows, were restored to their original state after meticulous expert decisions. In the Japanese case, however, the ancient repairs led to a change in the style of the structure, while in the Heisei restoration the structure was not restored to its original state, but rather the façade was restored to its presumed original style.

5. Conclusions and Implications

The concept of authenticity originated in Western heritage conservation theory. With increasing international exchanges and the publication of international conservation documents with East Asian characteristics, such as the Nara Document on Authenticity, countries such as China and Japan are paying increasing attention to authenticity. From a review of the Nara Document and the conservation documents of China and Japan, it is clear that the perception of authenticity at the theoretical level has been very profound, such as the need to pay attention to cultural diversity and the need for sources of information that can be used to judge authenticity; however, at the practical level, there seem to be no clearer and more accepted operational guidelines. Therefore, there are different results in different cases.

The restoration of the main hall of Nanchan Temple in the 1970s resembles a typical “stylistic restoration”. The main structure of the Nanchan Temple before the restoration belongs to the Tang Dynasty, but its appearance was modified several times by later generations and did not have a unified Tang style. After expert discussion, its Tang Dynasty style was restored, based on the treatise of Yingzao Fashi of Song Dynasty, and other architectural remains from the Tang Dynasty. The doors and windows, pedestals, rafter and tile elements, and ridge beasts were repaired and restored, giving the whole building a unified appearance with characteristics of the Tang Dynasty. In contrast, the main hall of Fogaung at Wutai Mountain, although also typical of the early Tang Dynasty, was not restored in a similar “stylistic restoration”, and, in a recent survey report (2011) [28], experts clearly suggested that restoration would might be detrimental to the authenticity and integrity of the building, and it was opted to preserve the building as it was.

The Toshodai Temple in Japan has undergone a relatively high number of restorations. As already mentioned, the restoration in the 19th century, during the Meiji period, and the changes in the early 21st century, during the Heisei period, are relatively significant. The two restorations reflect the social context of the different eras. During the Meiji period, new ideas, techniques, and materials from the West had spread to Japan, which is the reason why triangular-shaped roof elements appeared in this restoration. At that time, heritage conservation was also in its infancy in the West, and authenticity had not yet become a widespread concern, which was also reflected in the Japanese approach: the use of materials and techniques which were popular at the time, without concern for the authenticity of the physical fabric. The restoration in the Heisei period occurred at the beginning of the 21st century, when the Venice Charter had become an international consensus, the Nara Document on Authenticity had received international recognition, and authenticity had become a key concept in the field of heritage conservation. However, the restoration involved a major alteration to the temple itself, as can be seen from the façades before and after the restoration. Is this approach contrary to authenticity? This approach may be related to the Japanese tradition in the restoration of ancient buildings (replacing elements or even rebuilding), but also reflects the uncertainties and unknown difficulties that may exist at the practical level, guided by the theory of authenticity.

We need to obtain a comprehensive and objective view of the restoration of the Nanchan Temple. Firstly, “stylistic restoration” is not advocated in China at present. The restoration took place fifty years ago, before the Venice Charter was introduced to China, and before authenticity was given the same importance in China, Japan, and even Europe, as it is today. Secondly, it is commendable that the restoration was carried out in accordance with the documents and physical materials, and that it was thoroughly documented, without any subjective imagination or conjecture. This follows the idea of conservation put forward by Liang Sicheng in the 1930s: restoration is carried out only when there is absolute certainty. Thus, the restoration of Nanchan Temple embodies not only certain limitations, but also progress. Combined with the restoration of the main hall of Foguang Temple, we can see that heritage conservation in China is increasingly focused on preserving historical information to the greatest possible extent, with increasing attention being paid to the principle of minimal intervention and increasing emphasis being placed on authenticity.

A comparison between the Nanchan Temple and the Toshodai Temple will allow for deeper comprehension. The restoration of the Toshodai Temple does not seem to follow “stylistic restoration”, i.e., restoring the temple to a particular period, such as the typical style of Tang Dynasty; the restoration was completed for the purpose of structural strengthening. This is very different from the situation in China, where, many ancient buildings were restored in a “stylistic restoration”, including Nanchan Temple, Zhengding Longxing Temple, the main hall of Hualin Temple in Fuzhou, and the main hall of Zhenru Temple in Shanghai from the 1950s to the late 20th century. The alterations to the façade of the Toshodai Temple, on the other hand, reveal that Japan also places less emphasis on the building’s original or former form, which is often very important in Chinese heritage restoration practice, and the authenticity of the physical fabric of the building in China is given great importance. This emphasis originates in Western heritage conservation theory. Now this emphasis has changed in the West. With the development of conservation theory, international perceptions of authenticity have become more comprehensive and shifted to focus on “authenticity” in different cultural contexts and the importance of non-material factors in the assessment of “authenticity”, rather than being limited to focusing on the original state of the physical fabric. This is in line with the restoration of the Toshodai Temple, but does not mean that we can excessively interfere with the physical fabric or alter the form of the building at will. Rather, we should consider the historical and cultural attributes of the act of replacing elements the material object itself and interfere with the material object with care, while keeping a good scientific record, which is often the soul of authenticity in heritage conservation. Such a shift would be very beneficial for East Asian countries such as China and Japan, where timber-framed buildings are predominant, and also increases the necessary responsibilities and challenges.