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Global Case Study Project on Reconstruction
Case Study: Sensho-ji Temple Main Hall 1. Sensho-ji Temple and its Context before the Earthquake
1.1 Description1
1.1.1 Location and Setting Sensho-ji is a Buddhist temple located to the east of Iwaki City (Fukushima Prefecture, Japan) on a hill overlooking the valley of the Natsui River (Fig.1, right). The Outer Gate stands next to the foot of the hill; from there, several flights of stone steps lead to the main compound near the top. The Main Hall stands in the centre, facing east; with the Founder's Hall to the south and the Priest's Quarters to the north. At the southeast corner the tombs of former priests are grouped in a small graveyard. The Inner Gate stands to the front, with the Belfry outside north of the steps.
1 This section covers the items "General Description", "Form, Function, Creation and subsequent Transformations",
"History, Ownership and Environment", "Social and Economic Setting", "Frameworks, Agents and Communication" under Fig. 1 General layout of Sensho-ji Temple in the early 18th century (left) and today (right) sections 1.1 and 1.2 of the matrix.
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1.1.2 Materials and Techniques The Main Hall of Sensho-ji is a timber-framed building. The main post-and-beam structure supports a large roof structure consisting of timber struts, tie beams and rafters. Sliding doors and wooden board walls are employed as interior partitions. Small plastered wattle-and-daub walls are set between the tie beams. Before the earthquake, the roof was covered with iron plates shaped as tiles (Fig. 2); originally the building had a thatched roof. Different species of wood are employed, including pine and cedar. In repair works, when substituting a decayed timber member becomes necessary, timber of the same species and grading is employed. This kind of timber is still available, although it has become increasingly difficult to obtain wood for the repair of timber buildings inside Japan (especially in the case of large members), and sometimes wood has to be Fig.2 The Main Hall of Sensho-ji Temple before the earthquake
imported. In this case, even if the species and grading is the same, quality and properties may differ. The Agency for
Cultural Affairs of the Japanese Government (ACA) has started a program of forests dedicated to the production of timber for the repair of heritage buildings in order to address this problem. Timber members are joined mainly through woodwork joints, with minimal use of metallic fasteners. Woodwork joints are also used for repair works to join old and new timber when the decayed part of a timber member is substituted (see 4.2). The type of joint depends on the position and structural function of the member. Joints also changed historically, tending to become more complex. When a member is substituted during repair work, the type of joint and the finishing of the member (plane, adze, etc.) are reproduced. Traditional carpentry techniques are required to carry out these repairs. Since 1975, traditional techniques required for heritage conservation (including carpentry) are protected, and courses for carpenters are subsidized by the ACA. Carpenters who work on the repair of heritage buildings are licensed through these courses.
1.1.3 Form and Design The Main Hall of Sensho-ji is 22.2 m wide and 17.9 m deep (Fig. 3 right, Fig. 4 right). It is single-storied, and covered by a hip-and-gable roof. The inside of the Hall is divided by a row of pillars into the worship area (gejin) to the front and the inner part. A corridor surrounds both parts. In addition, there is a veranda to the front and an entrance porch. The gejin is a large undivided space. The inner part has a raised floor and is further divided into the sanctuary (naijin) and two side rooms. Inside the naijin there is a main altar in the centre and two side altars to the rear; in addition, there is an altar attached to the rear wall of the south side room. On top of the main altar there is a raised coffered ceiling; on top of the corridor surrounding the building the rafters make up the ceiling. The rest of the building has a board and batten ceiling. Round posts
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are employed around the naijin and between the inner part and the gejin; in the rest of the building chamfered square pillars are employed. In Japanese temple architecture, the character and rank of the Fig.3 Floor plan of the Main Hall of Sensho-ji Temple, before (right) and after (left) restoration
building
is
through
often
expressed
elaborate
complexes
bracket
(kumimono)
supporting the eaves. In this building, bracket complexes are relatively simple. Together with the use of square posts, this confers the building a serene appearance, close in character to residential architecture.
1.1.4 Changes in Function and Form2 Sensho-ji was founded in 1395 as Buddhist temple belonging to the Nagoe sect of the Jodo School of Buddhism, one of the most important Buddhist sects during the early modern period in Japan.
Sensho-ji
became
important as one of the four centres for the education of new monks (danrin) belonging to this sect. Fig.4 Elevations and sections of the Main Hall of Sensho-ji Temple, before (right) and after (left) restoration
2 The account of the history of Sensho-ji and the transformations of the Main Hall is based on Okawa, 2016 and
Shinonaga, 2017. 3
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A fire in 1668 destroyed most of the temple, but it was reconstructed thanks to the support of the branch temples and the local feudal lord. The temple documents show that during its peak, in the late 17th - early 18th century, several buildings existed apart from those standing today (Fig. 1, left), including residences for the monks. At that time, Fig.5 The Main Hall of Sensho-ji Temple in 1671
there were as many as 248 branch temples depending from Sensho-ji. The present Main Hall was reconstructed after the fire in 1671. At the time of the reconstruction, the building had a hipped roof covered with thatch; the floor of the side rooms was not elevated; and the naijin was separated from the gejin and the side rooms through sliding doors (Fig. 5). Inside the naijin there were only side altars. There was a
Fig.6 The Main Hall of Sensho-ji Temple in 1682~1700
ceiling only on top of the naijin; and there was no floor in the front veranda. This layout is consistent with the use of the building as danrin: the open gejin is designed to accommodate a large number of student monks; while the closed naijin was a space for the private transmission of oral traditions. The side rooms were also employed as lecture rooms. Surveys carried out during the repair works after the earthquake (see 3.2.2, 4.2) have revealed the
Fig.7 The Main Hall of Sensho-ji Temple in the 1780s
detailed history of transformations and alterations of the building (Fig. 6~8). The main ones are: 
In 1682, the floor of the naijin and the
side rooms was elevated, the main altar was installed, and the inside and outside of the naijin as well as the elements separating the inner part from the gejin were painted. In addition, the ceiling of the side rooms and the gejin was installed (Fig. 6). 
In the late 17th century, the Priest’s
Fig.8 The Main Hall of Sensho-ji Temple around 1854
Quarters and a residence for monks were built to
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the north and south of the Main Hall respectively, and corridors connecting to these buildings were added, together with the floor of the front veranda (Fig. 6).
In the late 18th century, the sliding door between the naijin and the gejin were removed, and sliding doors were added between the gejin and the corridor (Fig. 7).
In 1854, an altar was added to the south side room (Fig. 8).
In 1902, the roofing material was changed from thatch to tile, the roof slope was reduced and the roof structure modified accordingly.
In 1964, the roofing material was changed from ceramic tiles to tile-shaped iron plates.
Sensho-ji lost progressively its function as danrin from the Meiji period (1868-1912). Consequently, the temple lost its main source of income, and maintaining its buildings became difficult. Around 20 buildings, including the residences for the monks, were demolished during this time. The danrin system was completely abandoned soon afterwards. Currently, the priest does not reside permanently in the temple and divides his time between Sensho-ji and another temple in Iwaki City. The number of parishioners that support the temple is also comparatively small.
1.1.5 Condition before the earthquake and vulnerability3 Due to the lack of funds to carry out maintenance and repairs, the building was in a poor condition already before the earthquake. By 1973, timber members especially on the south side were in an advanced state of decay and the whole structure was visibly leaning forwards, presumably because of the excess load of the tile roofing added in 1902. The temple, the parishioners and the municipality did not have the means to repair the building. By 1980 it was considered to be close to collapsing and the municipality renounced to designate it as cultural property because adequate measures for its conservation could not be taken. The building came finally under protection as a heritage resource at the prefectural level in 1991. However, thorough repairs were not carried out; only temporary measures, such as stabilizing the leaning by pulling the building with wires from the back, were taken in 2001. Thus, the building was in need of a major repair already before the earthquake and the damage caused by the disaster was multiplied by its poor state of conservation.
1.2 Designation and Recognition4
1.2.1 Official Designation The buildings and site of Sensho-ji became protected as cultural heritage at several levels through a 3 The account of the condition of the building before the earthquake is based on Fukushima Prefecture Board of
Education, 2003. 4 This section covers the items " Official Designation or Inscription ", " Scholarly Recognition", " Popular Recognition",
under section 1.1 of the matrix. 5
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gradual process. The Belfry was designated as a Tangible Cultural Property at the municipal level in 1984. The temple grounds were designated as a Historical Site and Place of Scenic Beauty at the prefectural level in 1987. In 1989, the Priest’s Quarters were designated as a Tangible Cultural Property at the municipal level; the Main Hall was not designated at the time due to its advanced state of decay. The Main Hall was en designated as Important Cultural Property at the prefectural level in 1991. Lastly, in 2004, the Main Hall, Priest's Quarters and Outer Gate were designated as Important Cultural Properties at the national level. There are five criteria for designating buildings as Important Cultural Properties at the national level: (1) outstanding design value, (2) outstanding technical value, (3) high historical value, (4) high academic value, (5) showing the special features of a particular school or region. In addition to meeting at least one of these criteria, buildings are required to be a representative example of their time period or typology5. The Main Hall of Sensho-ji was designated under criteria (1) and (3). The official description made at the time of the designation includes an architectural description of the buildings and the following evaluation: "Sensho-ji was an important temple as the main centre of the Jodo School in Northeast Japan, and one of the few danrin in the region. The size of the Main Hall and Priest's Quarters reflect its high status. The layout of the Main Hall, with an open gejin, a closed naijin, and two lecture rooms on the sides, as well as the unpretentious, sober design are appropriate to its function as danrin. Together with the Priest's Quarters and the Outer Gate, measures are taken for the conservation of the temple compound."6 Thus, the official description emphasizes the attributes of design and function; specifically, it points at the layout of the building, which reflects its function as a danrin.
1.2.2 Scholarly Recognition There are two main scholarly works on Sensho-ji: 1) Jodo-shu Nagoe-ha Danrin Sensho-ji Shi (History of Sensho-ji, a danrin of the Nagoe sect of the Jodo school, edited by T. Sato, 1995) is a study on the history of the temple, compiling primary sources such as the temple chronicles and documents. 2) Sensho-ji no Kenchiku (Fukushima-ken Kinsei Shaji Kenchiku Kinkyu Chosa Hokokusho - Hoi) (The Architecture of Sensho-ji - Report on the Emergency Survey of Early Modern Period Shrines and Temples in Iwaki Prefecture - Appendix, Fukushima Prefecture Board of Education, 2003) is the report of the architectural survey conducted in 2002, focused on its architectural features but reporting also the condition of the building at the time. Both works were explicitly cited in the official description that accompanied the designation of the Main Hall as Important Cultural Property. Since the start of the repair works after the 2011 Tohoku Earthquake, a number of papers have been 5 Criteria for the designation of National Treasures and Important Cultural Properties (Buildings), 1951, third revision
1996. 6 This official description can be consulted at http://kunishitei.bunka.go.jp/bsys/index_pc.html
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published by the conservation architects7. Their main focus is presenting the construction history of the Main Hall, detailing the transformations and adaptations that had been made since its original construction; this information became clear through the surveys made during the repair process (see 3.2.2, 4.2).
1.2.3 Popular Recognition The temple grounds are famous for its plum trees; during the blossom season it is a popular spot to enjoy the flowers. This was one of the reasons of the designation of the site as a Place of Scenic Beauty. Initiatives to attract tourists are mostly based on this feature. Most Buddhist temples are supported by a community of parishioners whose donations constitute its main source of income. However, as mentioned above, the main function of Sensho-ji was the education of monks, and its parish is relatively small. This makes difficult to gather the required funding for repair and maintenance. In order to fund the post-earthquake repairs, donations had to be actively gathered through several initiatives.
2. The Great Tohoku Earthquake and its Impact
2.1 General Description and Impact of the Event The Great Tohoku Earthquake (11 March 2011) was a magnitude 9.0 (Mw) earthquake with its epicentre off the northeast coast of Japan. It was followed by a tsunami that caused catastrophic damage to 500 km of coast, and caused the nuclear disaster of the Fukushima Daiichi plant. It had a lasting effect on the economy and society of all the north-eastern region of Japan, Fukushima Prefecture being one of the most affected areas. The human cost of the disaster is estimated in 18,434 persons missing or deceased8, most of them caused by the tsunami. The total cost of the damage was reported to be approximately 17 trillion yen (220 billion USD). Japan is an earthquake prone country, and earthquakes can be regarded as cyclical. The Great Tohoku Earthquake was nevertheless exceptionally intense. Records and traces of previous earthquakes in this region suggest that an earthquake of this magnitude affects the region every 600 years. Despite the large scale of the disaster, heritage buildings, especially wooden buildings, suffered comparatively mild damage. Several buildings registered as cultural properties at the national level were destroyed by the earthquake or tsunami; however, no buildings nationally designated as Important Cultural Properties or National Treasures collapsed, although some suffered varying levels of damage. Six areas designated as Groups of Traditional Buildings were affected by the earthquake, two of them (Makabe and Sawara) sustaining extensive damage9. 7
The chief conservation architects are H. Okawa and M. Shinonaga. Their papers on Sensho-ji are listed on the Bibliography. 8 Estimate as of March 2018 by the National Police Agency, Japanese Government. 9
A report on the damage to cultural heritage caused by this earthquake was compiled and published by 7
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2.2 Damage Sustained by Sensho-ji Temple As mentioned above (section 1.1.5), the Main Hall of the temple was in a poor state of conservation before the event. The earthquake worsened the condition of several issues that were already in progress. Cracks appeared on the ground in front of the building. Inside the building, cracks appeared in the mud walls, and the sliding doors were damaged. The general leaning forwards of the structure became aggravated. The level of damage suffered by other buildings in the temple precinct was also closely related to their condition before the earthquake. After the Main Hall, the most affected building was the Outer Gate. On the other hand, the Priest's Quarters, Belfry, Inner Gate, and other structures suffered comparatively minor damage.
2.3 Damage to the Significance and Values The described physical damage had a deep effect in the significance-defining attributes of the Main Hall. Regarding the material, the cracking of the mud walls and damage suffered by sliding doors meant that they could not be conserved in their damaged state and would need to be replaced. The form and design of the building were severely affected by the overall leanings and deformations. The leaning of the structure rendered it unsafe, with the risk of collapse becoming imminent. The building in its post earthquake condition could thus no longer perform its religious function.
2.4 Emergency Response In the early stage after the earthquake, the Main Hall was closed to the public as it had become unsafe. Wooden bracings were installed as a temporary measure in the Main Hall (Fig.9, Fig. 10) and the Outer Gate (Fig. 11) to prevent further leaning or collapse before a thorough damage assessment survey was carried out by the ACA.
the Japanese national committee of ICOMOS in 2011 under the title The Great East Japan Earthquake -Report on the Damage to the Cultural Heritage- (available for download at http://www.japan-icomos.org/pdf/earthquake_report_20111120.pdf). 8
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3. Post–event appraisals
3.1 Impact Assessment After the earthquake, a thorough survey of damage suffered by cultural heritage in the affected region was carried out by the ACA. In the case of the Main Hall of Sensho-ji Temple, the damage assessment identified significant issues Fig.9 Wooden bracings installed as emergency measure inside the Main Hall of Sensho-ji Temple
affecting the building before the earthquake, including decay of timber members due to rot and insect attack and leaning of the structural framework. These issues had been worsened by the earthquake damage. The conclusion of the assessment was that a major repair through complete dismantling and reassembly of the structure was necessary to return the building to a sound condition. This
kind
of
repair
through
dismantling
and
reassembly is commonly applied in the case of wooden buildings in an advanced state of decay, and the possibility of applying it in the Main Hall of Fig.10 Wooden bracings installed as emergency measure inside the Main Hall of Sensho-ji Temple
Sensho-ji Temple was being considered even before the earthquake.
3.2
Establishment
of
a
hierarchy
of
significance-defining elements and decision on the purposes of the recovery10 Three overlapping purposes can be identified in the recovery programme: first, correcting decay and damage; second, restoring the building to its most significant stage; and third, structurally reinforcing the building.
3.2.1 Returning of the building to a sound condition Fig.11 Wooden bracings installed as emergency measure in the Outer Gate of Sensho-ji Temple
The primary objective of the repair was returning the
10 This section of the paper covers items included in " Responses and Recovery Programme" and " Impact
Assessment" under Component 3 in the matrix. 9
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building to a safe and sound condition. Through the dismantling and reassembly method, overall leanings of the structure are corrected. Decayed individual timber members or parts of members are substituted by sound timber. The objective of this kind of repair could be described as returning the building to a condition of structural strength and stability as close as possible to the time of its construction.
3.2.2 Restoration of the building to its most significant stage During the repair process, and as a result of the discussions between agents on the cultural significance of the building and the new information that came to light through the surveys conducted in the dismantling process, it was decided to restore the building to its appearance in the late 17th century, when it was at its peak as a danrin (Fig. 3 left, Fig. 4 left, Fig. 6). The layout of the building during this period represents best the original function of the building: at this time, the naijin was a very closed space and the gejin a very open one. These features were lost after the alterations of the late 18th century, when the separation between naijin and gejin was removed, and the gejin was surrounded by sliding doors. On the other hand, the original appearance of the building just after its reconstruction in 1671 was considered to be incomplete, as the ceiling had not been installed and the corridors connecting to the adjacent buildings had not been built yet (Fig. 5). Thus, a hierarchy of significance-defining elements was established were the most important factor of the significance of the building was considered to be the design and layout features that represent its function as danrin. This hierarchy is heavily based on the official description made at the time of the inscription. In fact, part of the official description (“an open gejin, a closed naijin, and two lecture rooms on the sides, as well as the unpretentious, sober design are appropriate to its function as danrin”) is explicitly cited when explaining the reasons to carry out the restoration (Okawa, 2016). The decision to restore the building was agreed between the temple, the conservation architect and the ACA. A permission from the Ministry of Culture, Education and Science is required in order to make any alterations (including restorations) in the appearance of a building designated as Important Cultural Property. According to the Japanese system, a complex decision making process has to be followed in order to ensure that the restoration has a high level of academic accuracy. During the dismantling process, the conservation architects survey the building examining the traces of lost or changed elements. Through the interpretation of these traces, the history of the transformations of the building since its original construction is reconstructed (see 4.4). If they have enough data, the conservation architects would make drawings of the building at each stage of its history (Fig. 5~8). After consultation with surveyors from the ACA, the conservation architects would then prepare a proposal to restore the building to its most significant stage. This proposal must be backed up by the evidence gathered through the surveys. The proposal and supporting evidence is then examined by the Cultural Council, an advisory body formed by experts and academics. If the restoration is considered accurate, the Council would give its approval and finally a “permission to alter the appearance of the building” (in this case, to execute the restoration) will be
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issued by the Ministry of Culture. The policy of restoring a building to its most significant point in time is not uncommon in the case of major repairs of buildings designated as Important Cultural Properties in Japan. This tendency reflects a value system where the significance of these buildings is attached mainly to the architectural features that define them as belonging to a certain typology, style, region, or period. Later alterations that do not follow these features are considered to obscure the understanding of the significance of the building and removed or reversed. This is related to the fact that the number of buildings designated as Important Cultural Properties is relatively small (around 2,500) and that they are designated mainly as representative architectural examples from the academic point of view of architectural history.
3.2.3 Structural Reinforcement of the Building The structural reinforcement of heritage buildings is also common in Japan. The 1996 Kobe Earthquake was a turning point for this policy. Before, heritage buildings were exempt from meeting building codes and would normally not be reinforced. However, the Kobe Earthquake caused extensive damage to timber buildings, and it was considered necessary to ensure the safety of heritage buildings as well. When a major repair is carried out, a structural analysis is performed, and reinforcements introduced if necessary. The level of structural strength which the building needs to meet is decided according to its function and predicted number of occupants. The ACA publishes a Guide for the Anti-seismic Analysis and Reinforcement of Buildings Designated as Important Cultural Properties, which is applied nationwide for buildings with this level of designation. In the case of the Main Hall of Sensho-ji, the structural analysis concluded that the building was unsafe and required reinforcement. Adopted reinforcement measures include introduction of a reinforced concrete deep foundation, introduction of a steel frame inside the building, and insertion of additional timber bracing to improve the behaviour of the structure against horizontal loads (Fig. 12). These reinforcements are Fig.12 Reinforcing steel pillars and wooden braces inside the Main Hall of Sensho-ji Temple
introduced in the way that is considered less intrusive, and as far as possible in parts of the building that will remain concealed.
3.3 Drivers for the Recovery Two main stakeholders can be identified as drivers behind the recovery process: the temple and the cultural heritage administration. The motives behind these two drivers of the recovery are different but
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complementary: the temple is concerned with the recovery of the religious function of the building and its symbolic value as a landmark, and the ACA aims to recover the building's cultural significance as a heritage asset.
3.3.1 The Temple From a very early stage after the earthquake, the temple made clear its resolve to repair the damage suffered by the buildings and took part actively in the recovery process. The first emergency measures were taken by initiative of the temple, which has continued to record and publish the efforts towards recovery in a blog made available on its website11. The priest has also manifested his desire to recover and enhance the role of Sensho-ji as a city landmark related to the plum trees, contributing to the general social and economic recovery of the city.
3.3.2 The ACA The efforts of the cultural heritage administration were coordinated and leaded by the ACA. The ACA provides technical support and subsidies for the repair works. 1) Technical support: surveyors from the ACA assess the damage to the building and help to decide the intervention policy. Once the repair works start, they supervise the works and provide technical advice to the conservation architects (see 4.2.1). 2) Subsidies: the ACA managed and provided subsidies covering 85% of the total cost of the repair works (see 4.5).
3.4 Challenges for the recovery The financial burden of the repair works on the temple was a major challenge in the recovery process. As already mentioned, the lack of parishioners meant that money had to be gathered through ad hoc donations. The difficulty to bear the cost of the repair works and the maintenance of the building afterwards had an effect on the restoration plan. In the late 17th century, the building was covered with a steep thatched roof. The original plans included restoring also this roofing material. However, a thatched roof would require re-thatching roughly every 20 years. Although re-thatching would also be subject to subsidies, a percentage (usually around 50%) would have to be covered by the temple. In addition, as there is no dedicated priest permanently residing at the temple, the maintenance of the thatched roof would have been difficult. Given the current financial and management situation of the temple, it was considered unviable to restore the thatch roof. Instead, the original shape of the roof, with a steep slope, was restored, but copper plate was employed as covering material (Fig. 13). Roofing with copper plate is also a traditional technique in Japan, employed since the early modern period.
11 http://sensyouji.com
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Fig.13 Copper plate roofing
Fig.14 Repair of a decayed wooden pillar base using a woodwork joint
4. Actions and Timeframes
4.1 Programme Timeframe After the earthquake struck on 11 March 2011, a disaster recovery project for the Main Hall and the Outer Gate was started in December 2011. The actual repair works started in March 2012 and are expected to finish by December 2018. A report on the repair works will be published by March 2019 (see 5.3).
4.2 Repair techniques and methods The methodology of repair through dismantling and reassembly is commonly applied to timber buildings in an advanced state of decay. After carefully numbering and dismantling all the members of the structure, decayed members or parts of members are substituted by new timber of the same species and grading. The building is then reassembled correcting all leanings and deformations. One of the basic principles of the Japanese approach to the repair of heritage buildings is that traditional materials and techniques, as close as possible to those employed originally in the building, should be used when repairing or replacing damaged elements. This applies to carpentry repairs, but also to other materials and techniques, such as those employed for the plastered mud walls. Regarding carpentry repairs, traditional woodwork joints are used as the main repair method. Decayed parts of timber members are removed and substituted by sound new timber of the same species and grading; woodwork joints are then employed to join the original and the replaced parts (Fig. 14). Carpenters employ modern electric tools, but also traditional ones. When an original member is substituted, the finishing of the original member is reproduced in the new one using traditional tools (see 1.1.2). On the other hand, regarding the structural reinforcement of the structure (see 3.2.3), modern materials and techniques are employed, such as a reinforced concrete foundation and a steel framework.
4.3 Agents 13
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Apart from the drivers of the recovery, which initiated the recovery process and continued having a key role during its implementation (see section 3.3), we can identify the conservation architects and the craftspersons involved in the works as the agents who actually designed and implemented the recovery project.
4.3.1 Conservation Architects The design and implementation of the project is being carried out by conservation architects from the Japanese Association for Conservation of Monuments (JACAM). Architects working in the repair of buildings designated as Important Cultural Properties need to be authorized by the government. There are several levels of authorization, which are obtained after graduating from specific courses. JACAM is the organization in charge of organizing such courses, and at the same time the largest association of conservation architects in Japan. The regions of Kyoto, Nara, Shiga and Wakayama have their own dedicated conservation architects; for the rest of Japan, architects from JACAM are dispatched to take charge of repair works. This system ensures that conservation architects have a high level of specialization and share a similar training background. As a result, the repair methodology described above is applied consistently by most conservation architects all over Japan. Most large repair sites, including the Main Hall of Sensho-ji temple, are managed by a team formed by a chief conservation architect and an assistant conservation architect who work in a temporary office built in situ for all the duration of the works. This allows them to work closely together with the carpenters and other craftspersons, and to carry out detailed surveys of the building during the whole dismantlement and reassembly process.
4.3.2 Craftspersons Craftpersons including carpenters and plasterers also have to attend training courses sponsored by the ACA to master the traditional techniques required for conservation work (see 1.1.2, 4.4). Craftspersons with specialized knowledge of traditional techniques could not be found locally; they came from different parts of Japan to take part in the recovery works. Roofing with copper plate requires also a high level of technical skill, as the copper plates had to be laid adapting to the complex curved shape of the roof. Specialized craftspersons were in charge of the execution.
4.4 Basis for the Restoration As described above (3.2.2), during the recovery process the building was restored to its most significant stage. According to the Japanese policy regarding the restoration of buildings designated as Important Cultural Properties, the restoration is only carried out if there is enough information to ensure it will be faithful. Gathering this information through surveys of the building, interpreting it and drafting a proposal for
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the restoration is one of the main tasks of the conservation architects. In the case of the Main Hall of Sensho-ji Temple, the restoration implied changing the shape of the roof, and the typology and layout of the interior partition screens.
4.4.1 Restoration of the roof Surveys on the wooden members of the roof
Fig.15 Examples of evidence for the restoration of the roof
during the dismantling revealed that the struts supporting the original ridgepole had been cut, and a later ridgepole nailed sideways at a lower height (Fig. 15). In addition, mortises where the original rafters were inserted still remained on several roof beams. From these mortises, it was possible to deduce the original position and slope of the rafters. The analysis of these traces allowed making an accurate reconstruction of the original height, shape and slope of the roof: a hipped roof with an almost 45 degree slope (Fig. 4, left). Traces and documental evidence confirmed that thatch was the original roofing material. The roof was thus restored from a hipped-and-gabled roof to a higher and steeper hipped roof. The roofing material was changed from iron plates shaped as tiles to copper plates. Details such as the typology and decorative motifs of the ridge were designed using similar contemporary buildings and documentary evidence as a basis.
4.4.2 Restoration of the interior partition screens Mortise holes on the pillars between the Fig.16 Examples of evidence for the restoration of the interior partitions
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worship area and the inner part provided information on the position and typology of the
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former partition screens (Fig. 16). Details were designed using similar contemporary buildings as a basis.
In addition to these changes to the roof and partition screens, the shape of the entrance porch, the altars and other details were also restored. It can be concluded that the restoration has a high level of accuracy and is mostly objective and based on material evidence present in the building (although details and decorative motifs include a certain level of conjecture based on contemporary similar buildings). This level of accuracy is possible thanks to the advanced survey techniques applied by the conservation architects, whose training and specialization allows them to identify and interpret the traces in the building.
4.5 Resources and Costs The total cost of the repair works is estimated in 108,000,000 yen (1,016,000 USD). This cost was divided between the national, prefectural, and municipal administration, and the temple. The national administration funded the repair works through two kinds of subsidies provided by the ACA: disaster recovery subsidies and conservation and repair subsidies. The former type was allocated specifically for the recovery of cultural properties after the earthquake. However, disaster recovery subsidies cover only the cost of returning the building to its state before the earthquake, and the structural analysis and reinforcement. Thus, in order to carry out the restoration, it was necessary to use conservation and repair subsidies, which are regularly used to fund repair works of buildings nationally designated as Important Cultural Properties. This means that although the three objectives of the recovery mentioned in 3.2 were carried out at the same time as part of a single process, funding for objectives 3.2.1 (returning the building to a sound condition) and 3.2.3 (structural reinforcement) was separated from funding for objective 3.2.2 (restoration). Both in the case of disaster recovery subsidies and conservation and repair subsidies, the national administration covered 85% of the total cost of the works. The prefectural and municipal administrations covered around 10%, and the temple around 5%.
5. Outcomes and Effects of the Recovery Process The final outcomes and effects of the recovery process cannot be assessed at the time of writing (March 2018) as the recovery works are expected to finish by December 2018. Therefore, this paper will provide an account of the outcomes and effects achieved until now, as well as the expected future results.
5.1 Assessment of the Outcomes with Regard to the Recovery of the Heritage Resource The recovery process can be said to be effective in replenishing the significance-defining attributes. The building will return to a safe condition, recovering its religious function. Deformations and leanings that obscured the design will be corrected. The restoration can also be said to improve the readability of the
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original design features. Although a proportion of the material damaged before or during the earthquake was irreversibly lost, it was replaced with
similar
material
worked
with
similar
traditional techniques (Fig. 17, Fig. 18, Fig. 19). Out of the three objectives set by the recovery programme (see 3.2), the recovery of the sound condition of the building and the structural reinforcement could be achieved as intended. Fig.17 The Main Hall of Sensho-ji Temple after repair, in May 2018 (outside, from southeast)
On the other hand, the restoration had to reach a compromise between the ideal outcome (a perfect recreation of the building as it stood in the late 17th century) and the reality (limited human and economic resources for upkeep and management). As a result, the ideal thatched roof had to be substituted by a copper plate roof. It will be important to assess in the future if the recovery process could successfully address the issues that affected Sensho-ji Temple also
Fig.18 The Main Hall of Sensho-ji Temple after repair, in May 2018 (inside, from east)
before the earthquake. As previously stated (see 1.1.5), maintenance issues were one of the main causes of the poor condition and vulnerability of the building. The material recovery of the temple buildings will need to be completed management
with
adequate
measures
to
policies correct
and these
deficiencies. It also remains to be seen if the recovery of Sensho-ji Temple will have a positive effect in the overall economic and social recovery of the region, as the temple expected (see 3.3.1). The integration of the recovered Sensho-ji Temple in the overall cultural policy of Iwaki City will be a Fig.19 The Main Hall of Sensho-ji Temple after repair, in May 2018 (inside, from southeast)
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key factor in this question.
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5.2 Emerging Values and Sustainability12 As described above (see 4.2, 4.3) the repair works were carried out giving priority to traditional techniques and materials as the main repair method. In this sense, the repair works site was at the same time a capacity building site for craftspersons. Traditional carpentry, plastering, and roofing techniques are nowadays rarely applied outside the context of conservation work. However, such techniques can be regarded as an intangible side of built heritage. As such, it also needs to be protected; conservation of techniques and conservation of buildings are mutually dependent. The recovery process of Sensho-ji Temple can be considered to have contributed as well to the conservation and handing down of the traditional techniques associated with its construction and repair. Handing down these techniques to the next generation is necessary to make this repair methodology sustainable.
5.3 Documentation of the Recovery Programme Following the standard practice for the repair of buildings designated as Important Cultural Properties in Japan, the repair process was documented in detail by the conservation architects. A description of the repair works, together with photographs of the process, drawings, and as summary of the results of the surveys, will be published as a report at the end of the repair project by March 2019. Such reports are elaborated following a standardized format, defining their overall contents and structure. Regularly, around 300 copies of the report are printed and distributed among stakeholders, public libraries, related institutions and universities. The budget for the elaboration and publication of such reports is included in the general budget of the repair works, and subject to the same subsidies. These reports started to be published in the 1930s and today number over 2000.
6. Additional Comments The recovery of the Main Hall of Sensho-ji Temple was executed according to a very high technical standard. This allowed reusing a very large proportion of the original material in its original position. Complex carpentry techniques were applied to repair the original timber members, and their careful numbering and storing during the dismantlement ensured that their position was kept after the reassembly. By the amount of effort and resources dedicated, it is evident that the involved experts considered respecting this principle necessary in order to keep the cultural significance of the building. In addition, there were several favourable circumstances that allowed this kind of recovery to take place, including an efficient administrative framework, the participation of qualified specialists, and the availability of traditional materials and technical knowledge. It can be argued that if any of these conditions had not
12 This section of the paper cover items in " Values and Sustainability" under component 3 in the matrix, as well as items
under " Assessment of the Outcomes with regard to the Recovery of the Heritage Resource" under component 5. 18
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been met, the quality of the recovery process would have suffered significantly, and the loss of cultural significance would have been more important.
7. Details of the Expert Completing this Case Study Alejandro Martinez de Arbulo is an architect, working as a research fellow at the Tokyo National Research Institute for Cultural Properties, Japan Center for International Cooperation in Conservation. Trained in Spain, his PhD dissertation was a comparative study on the approach to the conservation of wooden built heritage in Japan and Spain. The author was not involved in the recovery process described above. The analysis in this paper was made on the basis of the cited bibliographical material, interviews with the conservation architects in charge of the recovery process, and a survey of the site of the recovery works in August 2018.
Acknowledgements The author would like to express his gratitude to the priest of Sensho-ji, Mr Hiromichi Endo for his cooperation in the publication of this paper, as well as to the conservation architects, Mr Masayuki Shinonaga and Mr. Shun Imazeki from JACAM for providing their knowledge and kindly explaining the repair work site. The on-site survey was funded by Kyushu University (project leader Prof. Toshiyuki Kono) and carried out with the cooperation of Prof. Tomoko Mori (The University of Tokyo).
Sources of Figures Fig. 1: Okawa, 2015a (modified by the author) Fig. 2, Fig. 9, Fig. 10, Fig. 11: http://sensyouji.com Fig. 3, Fig. 4: Okawa, 2015b Fig. 5, Fig. 6, Fig. 7, Fig. 8: Okawa, 2015a Fig. 12, Fig. 13, Fig. 14: taken by author Fig. 15: Okawa, 2015a (modified by the author) Fig. 16: Okawa, 2015b (modified by the author) Fig. 17, Fig. 18, Fig. 19: S. Imazeki (JACAM)
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Sato, T. (ed.), 1995, Jodo-shu Nagoe-ha Danrin Sensho-ji Shi
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Okawa, H., 2015a, “Fukushima-ken Juyo Bunkazai Sensho-ji Hondo Oyobi Somon – Hondo no Genjo Henko – Sono Ichi”, JACAM Report, 119, 20-27
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