Japanese Kofun in Maps given by a Spaceborne Digital Elevation Model based on Multiple Satellite Data Sets

Here we propose a study about the orientation of the Japanese kofun, spanning from Remote Sensing to geomancy. Japanese kofun are ancient burial mounds mainly constructed between the middle of the third century to the early seventh century CE. The term “kofun”, which means “ancient tomb”, is also used to indicate a period in the history of Japan that spanned from about 300 AD to 538 AD, the year of the official introduction of Buddhism in the archipelago. The larger kofun have a very distinctive shape and are usually defined as keyhole-shaped mounds. Actually, the Japanese term is zempō-kōen fun, which means “square in the front and round in the rear”, according to the geometric bases of the two mounds composing the kofun. Here, we consider how the kofun appear when seen from above, by means of satellites. We will see them in the visible imagery of Google Earth and in the maps of the Sentinel Hub. In particular, in the proposed discussion and according to its title, we will stress the possibility to use maps from Spaceborne Digital Elevation Models (DEMs) to analyze the locations of Kofun, the ancient tombs in Japan. The Digital Elevation Model here used is that proposed by Yamazaki, Ikeshima, Tawatari, Yamaguchi, O'Loughlin, Neal, Sampson, Kanae and Bates, in the Geophysical Research Letters, 2017, and implemented at the web site it-ch.topographic-map.com . On Kofun and their orientation, a large literature in Japanese exists: we will give references about related archaeoastronomical studies too. Details about the burial chambers in kofun will be also given: in some of them, the presence of two burial chambers inside is giving a direction coherent with the long axis of the tumulus. We will also recommend the reading of detailed discussions (in Italian), that have been provided by G. Poncini in the Enciclopedia dell' Arte Antica (1995) and M. Hudson about archaeology in Japan (2002). Literature on the funerary rituals of the Kofun Period are also proposed. In fact, the study here presented is not only a discussion of the use of remote sensing; it is a study aiming to investigate the orientation of the tumuli in their specific landscape, in the framework of the culture and religion of the period. Therefore, it is necessary to consider the Japanese geomancy too. Considering the results of the studies by Saito Tadashi in 1950s, who looked at the orientation of 394 tombs of the Early and Middle Kofun periods (3rd to 5th centuries), we can see that many of them are facing the south and west directions. We can tell also that the quarter which contains the less number of tombs is the north-east one. In geomancy, the northeast quarter is considered to be particularly inauspicious, containing the direction known as the "demon gate”. In Japan, this gate is referred to as Kimon, meaning ominous direction, or taboo direction.