Nara (Heijo) Palace Site Excavation Report XVII（2011）

　Research Reports of Nara National Research Institute for Cultural Properties, No.84

 

　Investigations of The First Imperial Audience Hall Compound 2

　Carried Out 1965-2005

 

　English Summary

 

　Independent Administrative Institution

　National Institutes for Cultural Heritage

　Nara National Research Institute for Cultural Properties　2011

　Investigation of the First Imperial Audience Hall Compound 2

 

　Chapter I Introduction 1

1 Background 1

　A Nara Palace Site Excavation Report XI and its time division 1

　B Site management and archaeological investigation 2

　C Restoration of the First Imperial Audience Hall 3

2 Organization of investigation 4

3 Publication of the report 5

　Chapter II Outline of Excavation 7

1 Excavation areas 7

　A Location and its setting 7

　B Survey and division of precincts 9

2 Summary of excavations 10

　A 28th excavation 10

　B 92nd excavation 11

　C 170th excavation 11

　D 177th excavation 12

　E 192nd excavation 13

　F 217th excavation 14

　G 262nd excavation 16

　H 295th excavation 16

　I 296th excavation 18

　J 303-13th excavation 19

　K 305th excavation 19

　L 311th excavation 20

　M 313th excavation 21

　N 315th excavation 21

　O 316th excavation 23

　P 319th excavation 24

　Q 337th excavation 25

　R 360th excavation 26

　S 389th excavation 27

3 Excavation log (excerpt) 29

　Chapter III Archaeological Site 51

1 Geographical setting of the First Imperial Audience Hall Compound 51

2 Changes of topography 52

3 Archaeological features 54

　A Before Nara period 54

　B Phase I 54

　C Phase II 81

　D Phase III 91

　E After Nara period 98

　F Features belonging to unknown period99

　Chapter IV Artifacts 101

1 Wooden tablets with inscription (mokkan) 101

　A Mokkan recovered from ground soil 102

　B Mokkan recovered from the deposit with wooden chips and charcoals in the western side of the Imperial Audience Hall Compound and southern side of the Pond SG8190 103

　C Mokkan recovered from ditch SD 3825 108

　D Mokkan recovered from ditches SD 12965 and SD 18220 113

　E Mokkan recovered from building SB 18500 114

　F Summary118

2 Roof tiles121

　A Round eaves tiles121

　B Flat eaves tiles134

　C Round tiles147

　D Flat tiles150

　E Demon tiles153

　F Cover tiles of hip rafter154

　G Filler tiles154

　H Ridge tiles155

　I Roof tiles with inscriptions156

　J Bricks157

3 Pottery159

　A Pottery recovered from the deposit with wooden chips and charcoals in the western side of the Imperial Audience Hall Compound 160

　B Pottery recovered from ditch SD 12965164

　C Pottery recovered from building SB 17870165

　D Pottery recovered from building SB 17871167

　E Pottery recovered from building SB 17874167

　F Pottery recovered from building SB 18140167

　G Pottery recovered from SX 18160168

　H Pottery recovered from pit SK 17910168

　I Pottery recovered from pit SK 17905169

　J Pottery recovered from pit SK 17907170

　K Pottery recovered from ditch SD 18155171

　L Pottery recovered from ditch SD 18143171

　M Pottery recovered from building SB 14200172

　N Pottery recovered from ditch SD 3825C173

　O Pottery recovered from pits SK 3831, SK 3832, SK 3833 and SK 3835 176

　P Pottery recovered from building SB 18500180

　Q Ink plates182

　R Pottery with inscriptions and drawings 182

4 Wooden objects193

　A Wooden objects recovered from building SB 18500 193

　B Wooden objects recovered from ditch SD 3825 198

　C Wooden objects recovered from the ground soil of Phase 1-2 204

　D Wooden objects recovered from other features and deposits 209

5 Metal and stone objects and coins 221

　A Metal objects 221

　B Earthen wares associated with metallurgy 223

　C Stone objects 224

　D Coins 225

6 Floral remains 226

7 Wooden pipes 227

　Chapter V Research Essays 229

1 Changes in features and reconstruction of topography 229

　A Changes in features of the First Imperial Audience Hall Compound 229

　B Drain system of the First Imperial Audience Hall Compound 242

　C Topography of the northwestern part of the First Imperial Audience Hall Compound 247

2 First Imperial Audience Hall Compound as seen from historical materials 253

　A Early Nara period: Phase of the Former Imperial Audience Hall Compound 253

　B Late Nara period: Palace facilities in the central district 269

　C Early Heian period: Palace of Retired Emperor Heizei and royal domain of former palace of Nara 283

3 Ritual associated with abandonment of building 299

　A Introduction299

　B Context of wooden objects recovered from the postholes of the East and West Towers in the First Imperial Audience Hall Compound299

　C Meaning of wooden objects recovered from the postholes of the East and West Towers in the First Imperial Audience Hall Compound 302

　D Meaning of building abandonment ritual using wooden effigy type A2 305

　E Conclusion305

4 Changes of the First Imperial Audience Hall Compound: View from the analysis of roof tiles 307

　A Context of roof tiles in the Former Imperial Audience Hall Compound 307

　B Roof tiles of the East and West Towers and their implications 309

　C Scenery of buildings in the West Palace 312

　D Anomalous roof tiles315

5 Pottery analysis317

　A Pottery recovered from the “brown layer with wooden chips and charcoals” 317

　B Pottery unearthed from buildings belonging to Phase II 320

　Chapter VI Conclusion 325

 

　English summary 329

　Tables of measurements of flat and round eave roof tiles 342

　Interpretations of mokkan inscriptions (excerpt) 360

　Colophon and abstract

 

Summary

　This volume is the second report on excavations in the precinct of the First Imperial Audience Hall at the Nara Palace site.

　The quest toward reconstruction of the Nara Palace’s central portion had already begun in the mid-nineteenth century, with Kitaura Sadamasa’s “Heijokyu Daidairi ato tsubowari no zu” (Map of Land Divisions of the Greater Imperial Palace at the Nara Palace Site), which indicated in 1852 the results of his research on the Nara Capital. On this map, drawn with extreme accuracy from the perspective of surveying precision, an area 8 did square (1 did =133.1 m) corresponding to the remains of the Nara Palace is outlined with an extra thick red line, and labeled “Heijokyu” (Nara Palace) in red. Place names evocative of palace facilities, such as “Daikokuden,” “Omiya,” and “Dairi no miya” are clearly marked, showing that Sadamasa was cognizant of the location of not only the palace, but also its key components.

　Research on the Nara Capital experienced a hiatus around the time of the Meiji Restoration, but was re-initiated by Sekino Tadashi toward the end of the first decade of the twentieth century. With regard to the central portion of the Nara Palace, while it was unavoidable for a stage in which research had to stand upon the forms of surviving building platforms, plus land divisions and place names, Sekino developed his understanding of what today have been clarified as the Second Imperial Audience Hall and the State Halls Compound of the eastern sector as the sole precinct of central palace facilities. At that point, the precinct of the First Imperial Audience Hall, the subject of this volume, was inferred as possibly the Nan’en garden seen in historical documents. 1

　From the 1960s on, archaeological investigation of the central portion of the Nara Palace has been carried out continually by the Nara National Research Institute for Cultural Properties, and it has been shown that precincts of the State Halls Compound existed at two locations, a central one and another to the east. This was perceived to be the result of a move from the central to the eastern sector, and they were labeled the “First State Halls Compound” and the “Second State Halls Compound,” while a similar understanding formed of the “First Imperial Domicile” and the “Second Imperial Domicile.”

　Meanwhile, from excavation in 1970 to the north of the “First State Halls Compound,” a foundation platform was ascertained having a scale greater than that of the Imperial Audience Hall surviving in the east, at a spot which had been referred to from the past as “Daikoku no shiba” and “Daikokuden.” As it was then recognized that the horizontal dimensions of the newly discovered platform matched those of the Imperial Audience Hall which remains at the site of the Kuni Palace, in addition to validating the Shoku Nihongi account of the Imperial Audience Hall being moved from Nara to Kuni, the fact of the initial Imperial Audience Hall at Nara standing due north of the “First State Halls Compound” was clearly established.

　In a 1978 excavation at the Second Imperial Audience Hall, the one situated to the east, remains of a large-scale embedded pillar building were discovered in the strata below the foundation platform. From the 1980s, excavation of the “Second State Halls Compound” proceeded, and it became clear that for all six buildings in the eastern half of the precinct, the strata beneath the foundation platforms had embedded-pillar buildings of nearly the same scale as the overlying State Halls buildings. In other words, the central and eastern State Halls Compounds existed in parallel from the start of the Nara period, and as the previous explanation of a change from a “first” to a “second” compound was not appropriate, the labels were subsequently changed to “central State Halls Compound” and “eastern State Halls Compound.”

　The Second Imperial Audience Hall, which occupies the position of main hall in the State Halls Compound of the upper strata in the eastern sector, is regarded as having been newly built during the Tenpyo Shoho era (749-757), after the return of the capital to Nara in 745. The view that the embedded-pillar building in the strata below the Second Imperial Audience Hall was the Daianden is thought most plausible, and it is regarded as having been planned and built along with the State Halls Compound of the eastern sector’s lower strata to its south, and the Imperial Domicile to its north, at the start of the construction of the Nara Palace. The Imperial Domicile was maintained throughout the Nara period at the same spot, with revisions in the layout of buildings within the precinct dividing broadly into six phases. In contrast, after the return of the capital to Nara, in the precinct where the First Imperial Audience Hall had stood a group of embedded-pillar buildings, inferred to consist of about 27 items including the largest one in the palace site having pillars within the core, was built with precisely laid symmetry.

　According to documentary materials of the Nara period, as names related to the residences of the emperor, the three principal consorts, and the crown prince that were maintained within the precincts of the Nara Palace, there are Dairi, Chugu, Chuguin, Toin, Togu, Saigu, and so forth, and debate regarding the determination of times and places for the existence of each has been conducted repeatedly from the past. Discussion of this topic has developed based on the latest results of archaeological investigations not only at the Nara Capital, but at every royal palace and capital city of ancient times, and various new facts and perspectives have been presented. In the current volume as well, based on new results from excavations of the Imperial Audience Hall Compound cloister and environs, which have proceeded since the publication in 1982 of vol. XI of Heijokyu hakkutsu chosa hokoku (Nara Palace Site Excavation Reports) (hereafter Heijo hokoku XI), the initial report on the First Imperial Audience Hall, it has been possible to take the above-mentioned research on ascertaining the residences to a much deeper level. The details are covered extensively in this volume’s Chapter V, under Section 1 “Iko hensen to chikei fukugen” (Changes in features and reconstruction of topography) and Section 2 “Shiryo kara mita dai ichiji Daigokuden’in chiku” (The First Imperial Audience Hall Compound as seen from historic materials), but an outline will be given here, along with comments on tasks for further research and on the overall changes in the central portion of the Nara Palace.

 

　Phase I

　Phase I was the time of the start of construction of the Nara Palace, when the First Imperial Audience Hall was raised, which together with the tamped-earth wall cloister formed the First Imperial Audience Hall Compound. It divides into four subphases.

 

　Subphase 1-1 (Wado 3.3 to Reiki 1[710-715]). This is assessed as the time of construction of the First Imperial Audience Hall Compound. The first stage was completed around the end of 714, with the erection of the First Imperial Audience Hall (SB7200), the south gate (SB7801), and the tamped-earth wall cloister (SC5500, SC5600, SC7820, SC13400, SC8098). At this time, construction in the central State Halls Compound precinct had still not begun, with the first ground preparation thought to have been conducted around 715. At the surface of this ground preparation, excavations had been made for a north-south fence (SA8410) and for laying down a pounded layer of groundwork (SX9199), but both were reburied in an unfinished state. The ditch SD3765 functioned as a main route for drainage.

　In this manner, in the several years starting from the move to the capital in 710, palace facilities to the north of the central entrance on the Nara Palace’s southern side, the Suzaku (Otomo) Gate, remained in an undeveloped state. It is not possible to tell immediately whether this was because the urgent reason for the move to the Nara Capital bore no direct relation to these facilities of the central sector, or whether it was because the construction of the set of large-scale palace structures standing on pillar base stones, beginning with the Imperial Audience Hall, took a long period of time, but this remains an important task for future analysis.

　In the eastern sector at this time, the Imperial Domicile, the Daianden, the State Halls Compound of the lower strata, and boundary fences surrounding each of these were built as embedded-pillar structures, sharing an axis extending north from Mibu Gate. The eastern sector State Halls Compound of the lower strata was completed by 713 or 714 at the latest. The Imperial Domicile of this period was the first phase for that structure, which served as the residence of Empresses Genmei and Gensho.

 

　Subphase 1-2 (Reiki era to Tenpyo 12 [715-740]). This is the phase when the State Halls Compound of the central sector was constructed, and preparations of the environs of Saki Pond (SG8190) on the west side of the First Imperial Audience Hall Compound were begun, and the East Tower (SB7802) and West Tower (SB18500) were added on the southern side of the compound’s tamped-earth wall cloister. From the Reiki (751-717) into the Yoro (717-724) eras, a second ground preparation was conducted at the State Halls Compound and the boundary fences SA5550A, SA9201A, and SA9202 were erected, but at this phase there were no facilities for closing off the compound such as a gate. In conjunction with this, the main drainage route was changed to ditch SD3715. Next, a third ground preparation was conducted, and the State Halls SB8400 and SB8550, and a gate (SB9200) on the south side of the compound were built. In this interval, in Yoro 1 (717) the central sector State Halls Compound was called Saicho. This was the second phase of the Imperial Domicile, and as the residence of Emperor Shomu for the first half of his reign, a considerably richer complement of facilities had been built in comparison with the first phase. To the west side of the First Imperial Audience Hall Compound, Saki Pond (SG8190) was readied around the end of the Yoro era. The East (SB7802) and West (SB18500) Towers were subsequently added to the southern side of the tamped-earth wall cloister, and judging from the date of a mokkan (wooden document) recovered from a pit (SX8411), it is highly likely this was around Tenpyo 3(731).

　For the East Tower, a slight discrepancy has been pointed out for this inferred date of construction and the age of the eaves tiles of the roof belonging to it, but as discussed in Chapter V of this volume, in Section 4 “Nokigawara kara mita dai ichiji Daigokuden’in chiku no hensen” (Changes of the First Imperial Audience Hall Compound: view from the analysis of roof tiles), a further deepening of analysis is felt necessary for eaves tiles regarding the question of how to assess the ending dates for the style 6304C flat eaves tile and the 6664K round eaves tile.

　The East and West Towers were added by tearing down portions of the tamped-earth wall cloister’s southern side, indicating they were not part of the initial design of the Nara Palace construction. Such a pair of multistoried buildings, while differing in terms of their positions, were in existence near the Imperial Audience Hall Compound of the Fujiwara Palace, and as they are thought to have functioned to manifest the dignity of imperial authority as tall buildings in the central portion of the palace, then their absence at the start of the Nara Palace's construction can only be regarded as somewhat difficult to understand. Perhaps it was a bit of trial and error in the division of the unified central portion of the Fujiwara Palace into the central and eastern sectors at Nara.

 

　Subphase 1-3 (Tenpyo 12-17 [740-745J]. This is the period when Nara temporarily lost its function as capital, with the repeated relocations to the Kuni Capital, Naniwa Palace, and Shigaraki Palace. The Imperial Audience Hall (SB7200) and the eastern and western sides of its tamped-earth wall cloister (SC5500, SC13400) were removed to the Kuni Palace, with the missing portions of the cloister at Nara closed off with north-south running fences (SA3777, SA13404). The central State Halls Compound was also provided with temporary partition fences (SA550B, SA12950).

 

　Subphase 1-4 (Tenpyo 17.5 to around the end of Tenpyo Shoho 5[745 to ca.753]). In Heijo hokoku XI it was considered that after the return of the capital to Nara in 745, there was a period in which the First Imperial Audience Hall area was revitalized, with the eastern and western sides of the tamped-earth wall cloister rebuilt. At present, from re-examinations based on the results of subsequent investigations, it has become clear that the cloister was not rebuilt, and rather that by the first half of the Tenpyo Shoho era (749-757) following the return, palace facilities which subsequently functioned in Phase II were being built in the area formerly occupied by the First Imperial Audience Hall, and it has been judged that from around Tenpyo Shoho 5 (753) the southern part of the tamped-earth wall cloister (SC5600, SC7820), the South Gate (SB7801), and East and West Towers (SB7802, SB18500) were dismantled.

 

　Phase II

(From around the time of the Tenpyo Shoho to the first year of the Hoki eras [ca.749 to ca.770].) This is the period when the area in question functioned as an additional imperial residence, from the middle to the latter part of the Nara period. Over this time it was frequently called Saigu, and it is almost certainly the Saigu of Empress Shotoku’s reign in the latter half of this period. Empress Shotoku died in the shinden (main hall) of the Saigu in Jingo Keiun 4 (770).

　While it is very likely that a portion of the buildings remained from the Hoki through the Enryaku eras (770-806), their manner of use is not concretely known. In the central State Halls Compound to the south, the boundary fence was rebuilt as a tamped-earth wall (SA5550C).

　Parallel in time with Phase II, in the eastern sector State Halls Compound the12 State Halls were rebuilt as tile-roofed structures standing on pillar base stones, and came to be called the Daijokan’in. The Daianden, which had been an embedded-pillar building, was remade as a tile-roofed building in the same manner as the State Halls. This renewal of the building was carried out in the Tenpyo Shoho era (749-757). This was now the Second Imperial Audience Hall. In the precinct of the Imperial Domicile the construction of the third phase of structures was conducted. The large embedded-pillar tamped-earth wall which served as boundary partition up through the domicile’s second phase was taken down, and a tamped-earth wall cloister built in the same position. For both the time when this area was the First Imperial Audience Hall Compound, and for Phase II of that structure’s precinct (namely, when it was the Saigu residence, as the third phase of the Imperial Domicile precinct), a double-corridor tamped-earth wall cloister was used as the boundary partition. For government office and palace area boundary partitions at the Nara Palace, there were embedded-pillar fences, tamped-earth walls, single-corridor cloisters, and double-corridor cloisters, with the latter being superior among these as the highest status boundary partition. Subsequently the Imperial Domicile precinct underwent a fourth phase of rebuilding by Retired Empress Koken, then a fifth phase when it served as residence of Emperor Konin who ascended the throne in Hoki 1 (770), followed by a sixth phase as Emperor Kanmu’s domicile, coming thereby to the end of the Nara period. In that sixth phase, buildings corresponding with structures such as the Shishinden, Jijuden, and Joneiden, which comprised the Imperial Domicile of the Heian Palace, were present at the Nara Palace for the first time, establishing the framework for the Heian Palace.

 

　Phase III

(First half: Daido 4.11 (809) to Tencho 2.11 (825). Second half: from Tencho 2.11 thereafter.) The first half of this phase was the time of Retired Emperor Heizei’s palace (Heizei Saigu), but apart from the structure SB7803 which stood to the south of the palace, no prominent features can be ascertained in the State Halls Compound.

　The great majority of structures of Phase II are regarded as having continued their existence after the abandonment of the Nara Palace in conjunction with the transfer of the capital to Nagaoka in Enryaku 3 (784). In Daido 4 (809), the Heizei Saigu palace was built by Retired Emperor Heizei, and an attempt was made to return of the capital to Nara, but whether up to the time just prior to its construction the structures of Phase II remained or not is a matter that cannot be determined at present. One reason is that typological research on the recovered ceramics, and especially the work of ascertaining absolute dates, is not yet up to the level of providing precise answers to this debate. It remains a task for which further research should be undertaken.

In the second half of this phase, from Tencho 2 (825) on, the palace was maintained by a royal prince who was a son of Retired Emperor Heizei, but it cannot be ascertained in detail from documentary sources whether it was actually used as a residence, and it likely became more and more solely a base for managing the former Nara Capital estate.

 

　A half century has already passed since the start of programmatic and continuous investigation of the Nara Palace site through archaeological excavation by the Nara National Research Institute for Cultural Properties. During that time, research on the central portion of the Nara Palace has been undertaken as a priority, and academic reports have already been made public on the research results for the precincts of the First Imperial Audience Hall, the Imperial Domicile, and the Second Imperial Audience Hall Compound. The current volume has attempted an examination of the entire precinct of the First Imperial Audience Hall and its Compound. While it can be believed that the historical course of this precinct, which changed its aspect so strikingly from the first to the second half of the Nara period, has been made clearer, many tasks still remain. Henceforth, along with advancing analysis of results from research on the central and eastern sector State Halls Compounds, by promoting the investigation of areas not yet excavated which unfold from the periphery of the central portion of the palace, it is necessary pledge further clarification of the history of Nara Palace, and that of the Nara period itself.

 

　1 Sekino Tadashi, Heijokyo oyobi Daidairi ko (Considerations on the Nara Capital and the Greater Imperial Palace) (Tokyo Teikoku Daigaku, 1907).

 

2011年3月31日　発行

平城宮発掘調査報告XVII

奈良文化財研究所学報第84冊

第一次大極殿院地区の調査2

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