The controversy that has erupted in archeological circles around the
world since the discovery of an enigmatic structure, described by
some as 'pyramid-like', at Iseki Point just off
the southernmost Japanese island of Yonaguni-Jima, some 15
years ago, looks set to get even hotter as news emerges that the
so-called 'Yonaguni Monument' is just one of a number of
underwater megalithic structures in a 'complex' stretching
for many hundreds of miles north of Taiwan. As the sea-levels rose
at the end of the last Ice Age, the dry land that was once
between the Chinese mainland and Japan was inundated, and only in
the last few years has the attention of marine scientists been drawn
the existence of 'walls', 'stepped-pyramid-like
structures', and 'unusual artifacts' that have
been found underwater in the East China Sea.
One man above all others has made a study of the 'No.1 monument'
at Iseki Point over the past 10 years, and he is ideally qualified
to comment on the discoveries - being a marine geologist. His name
is Professor Masaaki Kimura, and in late June 2002 the
Morien Institute contacted him at the University of the
Ryukyus, Okinawa, Japan. Over the next few months we interviewed
Professor Kimura via email, and the following pages contain the
questions and answers that passed between us until mid-October 2002.
The interview is illustrated with some of Professor Kimura's
photographs and diagrams of the discoveries he made during countless
dives over the past 10 years ...
how long have you been studying the underwater structure off the
coast of Yonaguni Island at Iseki Point?
"I have been
studying it during 10 years."
I have read that
scuba diving is one of your interests. During the past 10 years, how
many dives have you personally made to study the structure at Iseki
"More than 100
I understand that
certain features have been allocated specific names, such as 'the
triangle pool', 'the loop road', and the 'arch-gate'.
Can you explain why these names were assigned to those particular
features of the underwater structure at Yonaguni?
Prof. Masaaki Kimura:
Shape of the depression seems to be a triangle. It resembles a "Kaa"
that is an artificial spring for drinking water at Gusuku Castle
of ancient Okinawa. The gusuku means a castle including a
temple in ancient Okinawa."
What would you
describe as the most interesting feature, or features, of the
Yonaguni structure, and why?
Prof. Masaaki Kimura:
"A rock similar
to a face of a man, the height of which is about 7 m. Its
eyes are artificial and, a famous free diver, Jacques Mayol
liked them very much. Therefore, we call them "Jacques eyes"
One of the
features on the Yonaguni monument is the 'giant turtle'
that has been carved out of the living rock at the eastern side of
the structure. Are there any species of turtle known in the South
China Sea area, which have ever been known to grow to this giant
"I do not know
its species. Living turtles may grow about 1.5 m long."
I am told that
all Japanese school children are familiar with the Okinawan fable of
Urashima Taro, the gentle fisherman who saved a young
turtle from bullies and released it into the ocean, only to be
visited by a 'giant turtle' who offered him, for his kindness, a
ride beneath the sea to a magical kingdom. Could this fable be a
folk memory of the 'giant turtle' carved onto the Yonaguni
"I do not know
the direct connection. However, the fable of Urashima (name
of a fisherman) is related to this kind of turtle."
Can you give any
details about the stone tools and other artifacts that have
been found on the seabed in and around the Island of Yonaguni?
several pieces of stone tools. Typical ones are adzes. They
are not polished. Their age is estimated as up to 10 thousand years
Professor Kimura and his
students have a variety of artifacts, including carved stones with
recognizable symbols, and a number of underwater megaliths showing
distinct evidence of 'toolmarks' similar to other examples of
'quarry marks' found on Yonaguni-jima (island) itself, have
been discovered during the course of more than a hundred dives
Yonaguni-jima over the past ten years ...
Carvings of symbols on one of those artifacts, a 'line-engraved
stone tablet', are said to be similar to the artifact that has
become known as 'The Okinawan Rosetta stone'. Can you
speak about the history of the 'The Okinawan Rosetta stone', and
also of the 'line-engraved stone tablet'?
Kimura: "More than 10 sheets of tablets called 'Okinawa Rosetta stones'
were discovered about 60 years ago at the western coast of
Okinawa-jima (island). There exist similar symbols to the '+'
and the 'v' carved on the submarine tablet."
Are there any other artifacts with symbols or recognizable shapes
carved on them that have been found underwater?
Prof. Masaaki Kimura:
"We recovered a big cobble with relief of four-legged animal found
Are there any symbols found carved directly into the rock, either on
the Yonaguni structure itself or nearby?
Prof. Masaaki Kimura:
"Some symbols are
carved on the western part of Yonaguni Pyramid (the westernmost
island of Japan) and on the upper surface of the Kusabi
(wedge) rock. It is not certain if they are artifacts."
I have seen
photographs of the 'main' and 'upper' terraces on the
Yonaguni monument, and also of the 'loop road' that winds
around the bottom. What aspects of these features convince you that
ancient peoples once used them as such?
Kimura: "There are holes
estimated to be used for pillars and drains for water on the upper
I gather that
more evidence is coming to light about the methods used by ancient
people to split the rock using wedges, and that this is true for
samples both underwater off Iseki point and also on the
island of Yonaguni itself. Can you give more details about
Kimura: "There are many
quarry marks on and off Yonaguni."
In February 1999
you presented a paper to The 11th Annual Symposium on Maritime
Archaeology and History of Hawaii and the Pacific. Reading from
the abstract, I was intrigued that you said, "The underwater
structure off Yonaguni Island is called No. 1 monument or Iseki
Point." Does that mean there are other monuments, maybe a No. 2
or No 3 monument, and if so, what are their locations?
Kimura: " No.2 - 5
monuments are surrounding the No.1 monument."
There seem to be many
features on land, both in Okinawa and on Yonaguni-jima, that are
similar to features of some of the structures found underwater. This
is particularly true of the 'gusukus', which is the word in
Japanese for 'castles'. Collectively, the structures found around
Yonaguni-jima are only a small part of a much larger 'complex' of
megalithic structures that stretch almost from the east coast of
Taiwan to the Korean Peninsula - all areas that were above sea-level
during the last Ice Age ...
Morien Institute: According to
the abstract, at the Hawaii symposium you also said that the
Yonaguni structure resembles ancient Okinawan castles such at
Shuri Castle and Nakagusuku Castle on Okinawa Island. How
old are these castles, and who built them?
gusukus such as Shuri Gusuku Castle (the most important
building in Okinawa, now) were built about 500 years ago. The names
of who built them are well known. They are "Aji" - the same
as a "king" in Europe."
Morien Institute: From the map
I see that there are another two structural features some distance
from the Iseki Point. These have been named as 'the
stadium' and 'Goshintai'. Can you reveal when they were
discovered, and why these features came to be so named?
Prof. Masaaki Kimura: "A feature
similar to a stadium in also found 200 m southeast of the No.1
monument. "Goshintai" means symbolized of "God", however it
is thought to be a solar clock. We call it "Teda-ishi" (sun
Morien Institute: Are we then
talking about a 'complex' of megalithic structures around
Yonaguni Island, and does this complex reach as far as Okinawa
and other Japanese Islands?
Prof. Masaaki Kimura: "I think the
complex reaches as far as Okinawa and other Japanese Islands where
the Jomon Culture was since 16,000 years before
Morien Institute: There are
topographical features which some have said are 'ancient
structures' underwater off the coasts of the Kerama
Islands, Aguni-Jima and also Chatan. Do they have any
features in common with No. 1 monument at Iseki Point off Yonaguni
Kimura: "They show in
part a similar structure to a stepped pyramidal one off Kerama
Islands, and a stepped broad terrace off Chatan near Okinawa
mainland. Scientific data, however, are lacking in both."
Morien Institute: I am given to
understand that the Okinawa Culture is different to that of
mainland Japan. How old would you estimate the Okinawa Culture to
Okinawa Culture has been said to be different to that of
mainland Japan. The Okinawa one is said to be newer, since 12
Centuries. The oldest man in Japan, however, was found in Okinawa.
For my idea, it would be 10,000 years old."
Morien Institute: Do you think
that the ancient Jomon Culture of Japan 10,000 years ago
could in any way influenced the design, and the position in the
landscape, of the structures that you have found in the Yonaguni
Kimura: "I can see
many common cultures of stones such as stone circles and monuments.
However, there is definitely a difference between the Jomon
and Yonaguni Cultures as regards the construction. The former
showed only holes used for poles excavated in the mudground, but the
latter did megalithic pyramidal structures."
Morien Institute: Before the
series of abrupt glacier-melting at the end of the last Ice
Age, the whole area from what is now the Korean Peninsula, to
Indo-China, was above sea level, with Okinawa being high mountains
near the then coastline. Do you think that there might be many more
underwater discoveries of monuments, and urban complexes, in the sea
between modern mainland China and Okinawa?
Kimura: "Yes. I think
so. Not only the area you refer to but also around the world. There
would be some difference as for urban or non-urban cultures due to
the various places."
Morien Institute: Do you think
that Okinawa, and the Ryukyu Islands chain, could have been
the major ports for maritime trade amongst the peoples of the last
Ice Age for whom it was only possible to live in those
Prof. Masaaki Kimura: "Okinawa
could have been the major ports for maritime trade after the last
Ice age. Before it, the transportation had been along the land
bridge from the Chinese mainland via Taiwan and Okinawa to the
Japanese main Island during the last Ice age."
Morien Institute: Could the
Yonaguni No1 monument have been used as a jetty for ships to
load and unload cargoes once the sea levels had begun to rise?
Prof. Masaaki Kimura: "Originally,
the No.1 monument should have most been used as a jetty but also as
a Gusuku mixed with Shrine and Castle. It would have been
used only as a jetty when the sea level had begun to rise, because
the place would then be too isolated in the ocean."
Morien Institute: All
measurements I have seen so far of the No. 1 monument tend to be
approximations given in metric units, with the exception of some of
the inscribed stones where they are precise, but still given in
modern metric units. Has any study been undertaken using traditional
Japanese or Okinawan units of measurement such as the 'sun',
the 'shaku', the 'ken' or the 'ri'?
Kimura: "I do not
research on metric units on the submarine monuments. Someone said
Jomon units would have been used as a part of the monuments."
Morien Institute: When it
comes to evidence that Iseki Point was once well
above sea-level, does the discovery of the Yonaguni 'sea-floor
stalactite cavern' by Mr. Youhachirou Izumi, of
Yonaguni Diving Service, now put this fact beyond
it comes to evidence that Iseki Point was once well above
sea-level, the Yonaguni 'sea-floor stalactite cavern'
has been studied by me with scientific methods and now put
this fact beyond dispute."
The sea-floor 'stalactite
cavern' was discovered by Mr. Youhachirou Izumi, of the Yonaguni
Diving Service, and has been extensively studied by Proff. Masaaki
Kimura and his students at the University of the Ruykyus, Okinawa.
As can be seen from the image below showing a diver exploring inside
the cavern, the 'stalagmite', which obviously formed
on the ground over many centuries has joined with the 'stalactite',
which formed over a similar period from the ceiling downwards. They
are formed 'only' on dry land, when weakly acidic rainwater or river
water seeps into a limestone plate, which then dissolves and
eventually drips through into the cavern. This is the only way that
this 'stalactite cavern' could have been formed - and it had to have
formed when the cavern was last above sea-level 10,000 years ago ...
Morien Institute: After
studying the No 1 monuments at Yonaguni for more then 10 years, at
what date would you now estimate it was last above sea level?
studying the No 1 monument at Yonaguni for more than 10 years,
the structure may have been manufactured in the dry air about 10
thousand years ago based on such evidence as age determinations of
the stalactite in the underwater caverns, and of the No.1 monument
using 14C and 10Be methods."
with Dr. Kimura