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The Thai Wreck of the Yamami site

It is traditionally known that Japan, during the Tokugawa or Edo Period (1603-1868), activated a strong closure policy that extended also to trade with foreign countries and the Asian continent in particular.

If this was generically true, then some underwater archaeological evidences dating back to that period and relating to commercial materials that came to light during various research activities carried out in the Kyushu seas are not explained. This group included the findings identified in the Yamami site in the seas of the island of Ojika (Nagasaki Prefecture), located in the Gōto archipelago, where, from 2009 to 2012, part of the research of the Kubilai Khan Fleet took place.

But what were those findings and why were they there?


Project history

As we said, the archaeological site of Yamami is located 100 m from the coast of Karamizaki at 5 m depth, between the island of Ojika and that of Nozaki in the Gōto archipelago.

In 1992, some fishermen identified and pulled up from the seabed some ceramic finds of Thai origin dating back to the 17th century. They were transport amphorae and immediately fishermen alerted the competent authorities.

In 2003, the ARIUA (Asian Research Institute for Underwater Archeology) carried out an initial investigation which, although limited, was characterized by the discovery of an intense deposit of ceramic artefacts all from Thailand.

Once the area was established as an "archaeological site", the investigations were set aside.

We will have to wait until 2011, when the Italian team, led by Daniele Petrella, commissioned by Hayashida Kenzō to investigate the site again.

The research extended over a larger area and led to the identification of a Thai wreck that was heading towards the shores of Kyūshū.

Also this time, the expedition was financed by the Ministry of Foreign Affairs and International Cooperation and by the Japan Foundation.



The channel that divides the islands of Ojika and Nozaki reaches the maximum depth of -31 m in a gradual manner, making that at 250 m from the coast the depth is still at -20 m and, in the site area, at -10 m. The main problem encountered is that it is located in a stretch of sea in which a current of 1 ½ knots is channeled especially when approaching the period of the typhoon which, once again, appears to condition the history of southern Japan.

From a technical point of view, the excessive current and the shallow depth of the seabed made investigation operations very difficult.

The seabed also has, like most of the Japanese coasts, massive rocky outcrops of volcanic origin, at least up to -10 / -15 m of depth and, therefore, 100/150 m from the coast before giving space to the not very compact sandy expanse of medium grain size and rich in quartz and shells, at least for what concerns the surface layers.

On the one hand, this conformation of the depths allows us to imagine the navigational difficulties that the wooden boats that crossed the canal had to incur, and therefore impose themselves as an essential fact in the reconstruction of the facts, but on the other it makes possible a scenario that would see the total disappearance of the wooden wreck which, sunk on the rocks and remained there for centuries not covered by sand, could be totally decomposed but, fortunately, this is not the only possible theory.

Starting from the small area already known, it was decided to further investigate the surrounding areas. Three consecutive survey rectangles of 50 m (SO / NE) x 60 m (NE / SO) were made to the north, for an area of 9000 m², one of 60 m (NE / SO) x 80 m (SO / NE) eastward, or an area of 4800 m², compared to the known area, in addition to the areas adjacent to the north-west and south-west coast of the site, for a total survey area of 13800 m².

Towards the north there were no further concentrations of finds, except for some sporadic fragments always related to the same typology of the known ones. In the south-east, very little ceramic evidence remains, decreasing until it almost disappears. This led to suppose that the wreck area was crushed towards the rocky coast. Important finds, in fact, took place in the south-west area, where other large quantities of transport ceramics were found and the further away we went, the more pottery finds were found for personal use and much finer, but always Thai.

In fact, what would be a trajectory of coastal current that would have moved the finds or the wreck itself, is interrupted by a real wall of outcropping rocks that would have accumulated the finds or stopped by impact the wreck.

The survey led to the identification of a very different area with respect to the surrounding seabed: an area of sand accumulated in the middle of a rocky area, under which, moving a few centimeters of sand, a further substantial accumulation of amphorae emerges. From the top, the sandy area perfectly resumed the shape of the boat. Let it be clear, that the lack of funds did not allow the use of a sorbon to deepen the survey.

Among the finds coming from the area to the south-east of the site, the most important was that of a conical-shaped lead ingot which is known to be used in Thailand to keep closed, during navigation, boxes used for the containment of various materials, including foodstuffs. Japanese archaeologists assert that this is a unique discovery, a small object that has always been sought after. Its dating dates back to the 16th-17th century.

The large quantity of ansated transport amphorae (with the typical small 4 ear loops) with a very large body, a rim of about 20 cm and a rounded lip, define the wreck as a merchant ship coming from Thailand and headed towards Kyūshū with three probable destinations: Hirado, an island that during the Tokufawa Bakufu remained open to contact with the outside also with the western countries, the Hakata bay, the most important city of Kyūshū with a large port, and Okinawa that hosted merchant ships and their loads.

The proposed dating for the materials found would be related to the period in question. From a comparison with the Thai amphorae found during the excavations of the Osaka castle it has been possible to advance a hypothesis. The stratigraphy of the excavation of the important castle has brought to light numerous Thai transport amphorae immediately below the layer dated (in a too precise manner) to 1625 placing the materials in question in an age preceding this year.

The reconstruction of the events that led to the sinking of the wreck is based, therefore, on the analyzed areas and the quantity of the identified finds. It is still not clear if the sinking took place due to the intervention of a typhoon or for other reasons; the answer can be found only with a deepening of the investigations and the analysis of all the evidences found.

In any case, taking the most plausible version, or rather that of adverse marine weather conditions, to be acceptable, the boat would have had to, in fact, travel the canal from south to north and therefore have been hit by the typhoon behind.

The discovery sheds new light on the cultural and commercial relationships that Japan entertained with other populations, in a period in which it was notoriously established a strong and decisive policy of closure towards other countries.

Goals achieved

The goals achieved were mainly:

  • Identification of the wreck

  • A new vision of the "closure" policy of Japan during the Edo Period.


What could still be done?

The expedition is now complete. It would be interesting to further investigate the area to identify any other wrecks.



- Daniele Petrella, director of the expedition.

- Samuele Carannante (Technical Director of the Marine Sub Company s.a.s.).

- Daniele Orefice (Collaborator of Marine Sub s.a.s.).

- Francesco Saggiomo (Technical Director of the underwater investigation company Idrosfera s.n.c.).

- Paolo Pecci (then a member of the Underwater Archeology Operations Unit of Archeologiattiva s.c.a r.l.).



ARIUA (Asian Research Institute for Archaeology and Ethnology)

Marine Sub s.r.l.


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diver at work in the Ojika sea
carta yamami.jpg
25.08.2011 153.JPG
22.08.2011 019.JPG
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