In this brief review I introduce recent publications on the archaeology of the Kawachi Plain, Osaka, Japan, in the Middle Kofun period dating to the late fourth to early sixth centuries AD (the Kofun or Mounded Tomb period is generally thought to have lasted from 240 to 600 AD). These convey an impression of the vast amount of information gathered in the past decade, as well as new syntheses.
In the fifth century, power shifted from the Nara Basin to the alluvial plains of Kawachi, bordering Osaka Bay. A new group of rulers achieved a new level of craft production, engaged in international trade, erected two burial grounds some 10km apart, and conducted burial rituals which emphasised military power by offering many iron weapons to their dead. In size, the largest tumuli, of mounded earth in the shape of a keyhole, with conjoined square front mound and rear round mound containing the main burial, rival the Chinese burial mound of Emperor Qin Shihuang and the Egyptian pyramid of Khufu. For example, the Daisen Ryo (Nintoku tomb) is about 850m in total length. Since the latter part of the nineteenth century the major mounds have been controlled by the Imperial Household Agency of Japan, as they are believed by some to be the resting places of the ancestors of the present Japanese Imperial Family. Such tombs cannot be excavated and archaeologists have limited access to them. Nevertheless there have been excavations of some large so-called royal tombs as well as surface finds and finds from the moats which surround the tombs. Many smaller tombs in the area, not protected by the Imperial Household Agency, have been destroyed by rapid urbanisation in the region. A substantial body of information has accumulated in the past 150 years but until now it has been very scattered.
In March 2008 Nara University published a 600-page report of a 3-year project to review existing knowledge of groups of large tumuli, principally the Furuichi and Mozu tomb groups of Kawachi (Shiraishi 2008). Nine faculty members of local universities and 10 members of local agencies for cultural preservation contributed to the research, which was funded by the Japan Society for the Promotion of Science. The publication is organised into four major sections. The first provides an exhaustive literature review and assessment of the present situation of the tombs. Previous excavations are summarised and a map of each mound at a scale of 1/2500 gives the location of each trench. The tabulated data include the excavator, reason for excavation, major features and artefacts, special information derived from the excavation, and site report reference. There have been about 300 excavations of the Mozu and Furuichi groups and 150 for the earlier Tamateyama group. The second section includes a discussion of the formation processes of the tombs, including local geomorphology and attempts to create a construction sequence using stylistic dating of local grey stoneware (sueki) and earthenware figures set on the tomb exteriors (haniwa). In the third section GIS data are presented and these are on a CD-ROM accompanying the report. Examples show aerial views, views from the Ishikawa River and from the sea, showing the silhouettes visible to people approaching from the sea. The fourth section includes 12 interpretive studies of the tombs and their contents. This publication is an immense contribution of exceptional value for research and reference.
For readers who wish to place the largest tombs treated above in a broader context, an excellent place to start is Ichinose's comprehensive synthesis of royal tombs and keyhole-shaped tombs (Ichinose 2005). He deals with chronology, tomb contents, the tombs of outlying chiefs, and changes in tomb construction. In the late third, fourth, and early fifth centuries, stone burial chambers were dug into the mounds from the top, while in the late fifth to seventh centuries horizontal burial chambers were built at ground level before the construction of the mound. The chronology of tombs has been based on the dated typology of the tubular haniwa set on the top of the mounds. In a final chapter Ichinose introduces data on palace sites and major areas of craft production.
Professor Ichinose has just published a general account of the fifth-century Daisen Ryo (Nintoku tomb), the longest in Japan (Ichinose 2009). From the time of its construction, regulation of tomb shape and dimensions was extended to other areas of Japan, suggesting the expansion of political control. Haniwa from some tombs in the southern Tohoku and Okayama regions display the same techniques of surface finish as those of Nintoku's Tomb, showing ranking, emulation and standardisation of production.
A recent exhibition catalogue deals with the second largest keyhole tomb in Japan, thought to be the tomb of Ojin (Figure 1). In 2006, the Osaka Prefectural Chikatsu Asuka Museum devoted its autumn special exhibition to this tomb, archaeologically referred to as the Konda Gobyoyama tomb of the Furuichi group (Osaka Furitsu 2006). The total length of the mound is 425m, while the total length including moats and ridges between the moats is 700m. The height of both the front and rear portions is about 35m. The main portions of the tomb remain unexcavated. The two outer ridges between the moats were covered with stone paving and rows of tubular haniwa. The ento (tubular) haniwa do not have black specks on the outer surface, indicating that they were not fired outside but in an enclosed kiln (Osaka Furitsu 2006: 110-11). They must have been made in the early fifth century when new methods of firing sueki were in use, using the tunnel kiln introduced from the Korean peninsula. From Ojin's tomb there is no report of grey stoneware from inside the mound, but from the outer ridge between the moats, sueki seems to be of TK73 type (Osaka Furitsu 2006: 111-12). A tree ring date of AD 412 from a wood sample from Heijo Palace is thought to date the TK73 type. This date is considered to be compatible with the available historical information on Ojin.
Haniwa in the form of water birds were found in the surrounding ditches of the Ojin mound. They are said to have been recovered in the dredging of the moat in the Meiji period (1868-1912). These water bird haniwa are now in the Tokyo National Museum. There are two size groups about 40cm and 60cm high. Some specimens in the Gaksuhuin University, donated by the Imperial Household Ministry before the war, came from the tomb around 1899. Water bird haniwa were also recovered from the nearby Tsudo Shiroyama and Suyama (Nara) tombs. From their occurrence they seem to be associated with royal class tombs. In the case of the Suyama Kofun there are other haniwa such as house, fence, shield, and parasol (kinugasa). Therefore it is likely that the haniwa around Ojin's tomb were set in a complicated arrangement. On the ridge between the ditches there were tubular haniwa, parasol-shaped haniwa, and other kinds of representative haniwa. Three fragments of wooden chairs or seats were also recovered.
In general there is a wide range of mound sizes and shapes in Furuichi and Mozu. However a particular feature of these tomb groups is the presence of what have been termed 'satellite mounds' (baicho), smaller round or square mounds near much larger, usually keyhole-shaped mounds. From the excavated examples, it is not easy to detect general trends: however Tanaka's analysis (2001) provides an authoritative discussion. The satellite mounds are considered by their general proximity to larger mounds to be dependent on the former, rather than independent burial facilities. Two types are recognised; those with grave offerings as well as human burials, and those with grave offerings alone. They are often square in plan and the burials occur in wooden coffins rather than stone chambers with stone coffins. The satellite tombs are considered to be a separate class from the small, medium, and large free-standing tombs; there are also cases of satellite tombs related to medium mounds as well as large ones (Tanaka 2001: 55). The status of the occupants of satellite tombs is thought to be different from those buried in independent burial facilities, albeit of different sizes. The assigning of tombs with burials to satellite status seems to depend on a subjective assessment of their spatial relationship to large tombs. Some appear to be devoid of burials, as if they were places for offerings alone. It is however not always possible, from limited excavation or accidental exposure, to be sure that a tomb does not contain a yet undiscovered burial.
In the Early Kofun period, at the time of the early-fourth-century Hashihaka Kofun, Nara, the large keyhole-shaped tombs stood alone, without smaller tombs or satellites. In the subsequent Yamato Yanagimoto tomb group of the Nara Basin, middle size tombs emerge, in addition to large ones and some satellite tombs appear. In the Saki tomb group of the Nara Basin (end of Early Kofun), there are three or four distinctive tomb groups but the ratio of satellite and medium tombs is low. A huge change occurs in the Mozu and Furuichi tombs of the fifth century. For Furuichi there are 7-10 satellites, 5-7 medium, and 11-14 mounds for every large mound. Some archaeologists have proposed that the satellite tombs were used for administrative officials (Tanaka 2001: 50). While Tanaka states that this is not entirely clear, he concludes that the proliferation of satellite tombs is an indicator of increased social complexity. Suzuki (2002: 68-72) interprets the satellite tombs as representing a 'primitive administrative class' (genshiteki kanryo). It seems to me that the grave wealth of this class tends to consist of utilitarian objects, perhaps produced under state control, rather than the ritual objects reserved for the hereditary elite. Tanaka (2001: 50) notes that the contents of satellite tombs are variable. Tombs such as Shichikan, Ariyama and Nonaka contain weapons and agricultural tools, while others such as Katonboyama contain many miniature stone replicas of tools and weapons.
One of the satellite tombs of the Ojin tomb provides an example of the relation between the different types of burials. The Konda Maruyama Kofun is situated to the north of the front square portion of the Konda Gobyoyama Kofun (Ojin's tomb) built in the early fifth century. A round mound about 50m in diameter, it appears to be a satellite mound of Ojin's tomb. Gilt bronze horse decorations found in the tomb show strong influences from the styles of horse ornaments originating in the three Yan Kingdoms of Northeast China. There were a clay surrounded wooden coffin (nendokaku), wood coffin, horse gear, a sword handle made of deer antler, iron arrowheads, cuirass and belt fittings. It is uncertain whether there were also mirrors and beads.
In 1848 a group of artefacts was excavated from the Konda Maruyama Kofun. They were kept in the Konda Hachiman Shrine and registered as National Treasures in 1952. The objects included two gilt bronze saddle bows decorated with dragon motifs, a gilt bronze bridle piece with mirror-shaped plaque, a deer antler sword handle, horse ornaments, and iron arrowheads and cuirass fragments (Tanaka 2001: 139). A number of scholars think that the saddle bows are continental and that the examples from Konda Maruyama and Kurazuka are similar. They date to the mid fifth century, and probably came from Paekche (in southern Korea) to Japan, or possibly from Koguryo (in northern-central Korea) to Paekche to Japan. They are similar to the saddle bow decorated with dragons found in a tomb in the Hyakuzukabaru tomb group of Saitobaru in Miyazaki Prefecture, some 500km to the southwest of the Osaka region. This similarity is thought to indicate a strong relationship between the Kings of Wa and local centres of power.
Fujita's recent study (2006) focuses on royal power and warfare. The abundance of weapons and armour is a hallmark of the Middle Kofun period (roughly fifth century). Fujita undertook a comparative study of the distribution of armour and weapons in Tomb Period sites throughout Japan, tabulating data on 239 cases, and seriating cuirasses and helmets as well as their earthenware haniwa representations. He concluded that in the fifth century there was a system of local military administrative centres with burials containing sets of cuirass and helmet, controlled by the Kawachi region, and that arms were distributed through this centre. Fujita linked his study of weapons to the satellite burial mounds (baicho) which are only found in Middle Kofun Kawachi. The Nonaka tomb of the Furuichi tomb group contained a large wooden box and a line of 10 sets of cuirass and helmet. He concluded that the person buried in the Nonaka tomb was an administrator of weapons and armour, an official attached to the occupant of the adjacent, huge, unexcavated Hakayama tomb, who was buried some years after the ruler's death. Fujita found that the Nonaka pattern was adapted by local elites. He postulates that another satellite mound, the Katonboyama mound, of Mozu, is the tomb of an official who was in charge of ritual activities. Its grave goods included 360 miniature soapstone swords and 725 soapstone magatama (comma-shaped pendants).
In addition to the burial mounds, excavations have revealed a substantial amount of information concerning the economy of the region. A palace area at Naniwa and warehouses at nearby Hoenzaka have been located on the low-lying spit areas near the centre of modern Osaka. At the Narutaki site, located in the narrow area where Osaka Bay opens into the Pacific, seven large warehouses have also been excavated. Furthermore, salt making sites have been found in a l0km zone along the old shoreline of Osaka Bay (Tanaka 2001: 434-39) and roads linking Kawachi with Osaka and the Nara region have been traced (Izumori 2006; Morimura 2006). Travellers approaching the area by sea would have seen the three huge tombs of rulers, Nintoku, Hanzei and Richu, lined up along Osaka Bay and would have passed by them on the Otsudo and Tajikido roads to Naniwa. Their great height (the rear mound of Nintoku's tomb is 35m high), and fresh stone facing would have been very impressive.
Vast numbers of kilns which produced a new kind of luxury and ritual stoneware have been recovered. A recent general description of the Suemura Kiln Site group was published by Hiroshi Nakamura in 2006 (Nakamura 2006). This group of at least 500 kilns in six zones lies in the Senboku Hills c.5-10km south of the Mozu tomb group. A large area of rural upland was transformed into a city in the past few decades, and nearby hills were levelled. These kilns were the first area of production of grey stoneware (sueki) in Japan. It is assumed that the rulers buried in the Furuichi and Mozu burial grounds had some sort of control over the production and distribution of wares from these kilns. The author concluded that sueki production began in the latter half of the Kofun period, since there appear to be no sueki vessels in the earlier tombs of at least the Mozu group. Production continued until the tenth century. Pollen studies show that by the sixth century a substantial portion of the fuel for the kilns came from secondary forest. Adjacent villages left by potters, some yielding substantial quantities of pottery from the Korean peninsula, were found. Low lying sites, too wet for human habitation, may have been loading points for water transport.
Ancient Japan: the archaeology of state formation (Hishida 2007) is an engaging treatment of craft production and some aspects of state formation. Professor Hishida mentions that his work is informed by debates at Kyoto University at the time of the 2003 project 'Comparative Study of State Formation'. He introduces the neo-evolutionary framework of Elman Service and includes comparative archaeology in his own fields of interest. He covers recent literature which clearly shows that in the fifth century there was unprecedented large scale production of ceramics and salt, iron working and bead making. New techniques were introduced by immigrant artisans from Korea in the fifth century, and in the sixth century intensive craft production spread to surrounding areas such as Okayama and northern Kyushu. The internal domain or core was pre-eminent and was linked to the periphery through a system of warehouses and administrators who managed labour and supplies. The political economy, i.e. the links between agricultural production, craft production, state politics and Kawachi tomb building are not clear from archaeological data alone and the textual information on the miyake administrative institution comes from the sixth and seventh centuries at the earliest. However Hishida's approach adds an invaluable dimension to the study of the fifth century kings of Kawachi and the ancient Japanese state in general.
Since the 1950s Japanese scholars have searched for archaeological clues to the evolution of the ancient Japanese state. The bestowing upon vassals of mirrors cast from the same mould indicates a third-century confederacy. Conformity to concepts of tomb construction and ranks of tomb size have also been studied, as has the distribution of weapons and armour in the fourth to sixth centuries. A very few late fifth-century inscribed swords seem to indicate the relation of regional vassals to the centre. A plethora of tabulated data amenable to all kinds of manipulation and display and a number of theories provide one of the world's richest case studies for the study of state evolution.
Recent scholarship on the fifth-century Middle Kofun period burials of the Kawachi Plain indicates a sudden increase in production of all kinds of goods, as well as the recruitment of labour for the construction of tombs which rival in size those of the Chinese Qin Empire of the third century BC. A new class of burial, the baicho or satellite burial mound, may belong to a sub-group of administrators, some of whom appear to be military figures. Recently accumulated information in books such as those presented above indicates a high level of state organisation supported by a flow of resources from beyond the confines of the Kawachi Plain.
Japanese state support for the preservation and interpretation of these magnificent Osaka sites has traditionally been generous but most recently very serious budget cuts have been proposed following a downturn in the local economy. The global importance of these sites cannot be exaggerated and all concerned fervently hope that new ways will be found to support public appreciation of these monuments and ensure funding for their general investigation, protection, and interpretation.
Thanks are offered to Ken'ichi Morimura of the Sakai City Board of Education, Ms. Yumiko Ogawa, Osaka Prefectural Board of Education, No. 1 Cultural Preservation Research Group, and Dr. Shinsaku Tanaka of the Ikeda City Museum of History and Folklore, for providing copies of invaluable research materials and offering valuable comments; and to Simon Kaner and the Sainsbury Institute for the Study of Japanese Arts and Cultures for continued support.