I've reproduced Mr Kameshima's work here so that we don't lose it should he ever decide to pull his work off the net.

Mystery & Romance of Ryukyu History

By Mr. Yasushi Kameshima

China, Japan, Korea and the South Pacific region... Historical links are revealed by the Japan Current and seasonal winds.

Originating in the North Equatorial Sea with a width of 200 kilometers, a depth of 700 meters and heading Northward 130 kilometers off the West coast of Okinawa island at a top speed of 10 km/hr, the Japan current is one of the largest ocean currents around. It passes a mere thirty kilometers off Kumejima Island.

This giant ocean current is easily distinguished by it's dark surface color caused by the abundance of plankton which it contains. In China it is known as the Kokuko. In Japan, as the Black Current, Hino-Hongawa, San-cho etc.

Monster flow of energy heading Northward.

The Japan Current pushs 50,000,000 tons of water per second out into the ocean. The amount of water used per day in Okinawa is approx. 500,000 tons, therefore enough water for 100 days use in Okinawa is pushed Northward every second by the amazing energy of the Japan current. In Summer the temperature of the current is 29 degrees Celsius, in Winter it still reaches an average of 20 degrees.

The air heated by the surface of the current also warms the air of the coastal regions that it passes by. The regions which the Japan Current affect are the following places near it's origin; Oceania, Polynesia, Philippines, China, Korea, Ryukyu Islands, Kagoshima, Nagasaki, Kumamoto, Fukoaka, Iki, Tsushima, Kochi Wakayama Mie, Shizoka Chiba, also a broad area up to Kinka-zan in Miyagi Pref. The current, which goes further North after the open waters of Kinka-zan where it collides with the North American Continent. After that it follows the coast of the continent around to the South where it finally arrives back at it's origin, the North Equatorial Sea.

The Japan current's grand endless cycle has been in continuous motion for the last 30,000 years. Boats and other items floating on the water's surface are easily swept along once they are caught up in it's flow. In addition, the current provided an abundant supply of fish which was important to the ancient people's diet. There's tuna, yellowtail, bonito, parrot fish, sardine, lobster and an eel whose breeding grounds remains secret even today.

Far away in prehistoric times, there was a tribe of sea faring people called the Kai-jin. These people followed the fish and moving from island to island sojourned Northward. The Kai-jin kept moving further and further North until eventually they reached the Japan islands. They brought their culture and civilization with them. It is thought that the Kai-jin influenced the dive fishing in Itoman, females divers in Saishu Island, Korea, the way of fishing in Iki and Tsushima Islands, also the fishing women in Ago gulf Ise. It is believed that fishing traditions in all these places were passed along from Polynesia. The families who served the imperial court by managing various fish such as Awabi (abalone), Kai (shellfish) etc were called kai-bu (sea groups). They originated from an oceanic race and came to Japan.

Using an ancient boat to travel by the Japan current flow

During 1975, the year when the Okinawan Ocean museum opened, there was an ocean event held to illuminate the history of the Japan current. In the South Pacific (Micronesia) there is Satawaru Island. As part of a big project commemorating the museum opening, five fishermen restored an ancient boat and set out from Satawaru Island to sail to the Ocean museum (on the main Okinawan island) via the flow of the Japan current. There is roughly three thousand kilometers between the Ocean museum and Satawaru Island. The fishermen sailed the distance and arrived safely at the museum in just thirty days!

They sailed across the ocean without the use of a radar, motor engine or indeed any other piece of modern equipment. Their navigational method was simply to follow the flow of the Japan current during the day and to let the North star (Polestar) guide them throughout the night.

When they were out in the open waters and there was not a shadow of an island to be seen they used the same survival techniques as the ancient Phoenicians. First of all, during the day they would trace along one island and catch sea turtles. The turtle meat would become food. Next they would gather coconuts. This is what they would drink. Then they would catch 5 or 6 small birds which lived on the island and take them on to the boat. When they reached open waters they would release the birds. These birds would fly high up into the sky, spot far away land and then fly off in it's direction. The boat would follow after the birds, continuing it's search for the next island.

Using a restored fishing boat and these kinds of ancient seafaring methods, they traveled an average of 100 km/day which enabled them to reach Okinawa safely after 30 days. This boat was made from approximately 8 meter long reeds.

Using seasonal winds to travel back down South

Now, how would travel in the opposite Southern direction be possible? Well, that was dependent on the energy of the "Seasonal Winds" which is our second keyword. Seasonal winds were used when heading back down South. Plus, after striking islands or peninsulas, the opposing current, which also headed South, was used too. In Okinawa a seasonal wind known as the new North wind (Mi-nin) blew from October to February of the following year.

Hawks and migratory birds called Sashiba, and occasionally plant seeds, etc all headed South, riding on the Mi-nin which blows from North to South. Then from about June, another wind (Hae) will start to blow from South to North in the opposite direction. The excellent Northern and Southerly winds which blow along the Ryukyu islands effectively divide the year into two parts.

The speed of the seasonal winds upon land is 7 or 8 knots, however on the sea it increases to 10 or 15 knots. From thousands of years ago ancient people used these winds to freely travel about on the sea. Every year around October the Ryukyu ships would leave the Naha harbor bearing tributes for China and first head for Kumejima island. They would anchor in at Kumejima and then take the Mi-nin Northern wind and travel onto Fukushu, China. Riding on the North wind it would take them approximately 8 days to arrive at Fukushu.

Why didn't they go directly to Fukushu from Naha? Why did they travel via Kumejima island? This was because it was the shortest distance to cross the Japan current from Kumejima. In order to cross the Japan current, which runs 30 kms off Kumejima island, the tribute ships had to catch a strong Northerly wind and succeed in one try. Otherwise they would be caught up in the Japan current and on occasion were swept up to Korea and Kinka-zan in Miyagi Pref.

Current and seasonal winds; an energy source that transported people

The natural energy of the Japan Current and seasonal winds carried an extremely important role in the transportation history of the Ryukyu people. The prehistoric peoples, ancient Jomon people, Yayoi people, ancient Chinese people, remnants of Heike family, the Wakan who ruled East China Sea, South East Asian and Koreans, all these people had a better knowledge and understanding than modern people of winds and ocean currents and so were able to utilize their natural energy.

The energy of currents and wind form an important part of Ryukyu history. However, even today this fact is not historically recognized much at all. It could be said that the early 15th century Ryukyu dynasty, which occurred during a time of free travel on the Asian seas where a theme of world interchange built a bridge to the world, was a dynamic Asian oceanic navigational era.

Sulphur Tributes and an Equestrian Mystery

Could Shuri-jo have been a military castle? And what is the deep connection between the Ryukyu Kingdom and the Japan current?

Were the ships bearing sulfur as a type of collateral security?

Why was Sulfur the number one tribute supplied to China by the Ryukyu Kingdom?

The Ryukyu Kingdom has sent sulphur as it's first and foremost tribute to China since the establishment in 1327 of the Shinko trade system (a system in which China was a suzerainty ) by Satsudo, a Chuzenkoku king. This tribute was supplied at the request of China where there was a sulphur shortage. The Sulphur supplied by the Ryukyu Kingdom was used by the Chinese to mix with niter, of which they had an abundance, together with charcoal to create gunpowder.

Wars have raged continuously one after the other throughout China's five thousand year old history. In contrast peace is said to have reigned for as little as fifty years. So regardless of the era, men in power there have always looked for new and more powerful weaponry. Needless to say the man who possesses a superior weapon can control the known world. For the Emperor of a great international power like China, the sulphur supplied by the Ryukyu Kingdom was an indispensable item for the creation of such weapons. In addition, the gunpowder would have been a necessity for flood control and the building river dams.

The sulphur shipments are mentioned within Ryukyu historical records, but there is no written record of the reason why such a tribute was paid. It is generally thought that the small Ryukyu kingdom would have secured special favors from the great international Chinese power as a result of the sulphur tributes.

One way in which China is assumed to have reciprocated is with the presentation of a two hundred tonne, world-class, large sized ship each year when the Ryukyus went to pay their tribute. There was no gesture of this kind ever shown to Japan.

There is thought to have been a permanent fleet of at least seven or eight world-class boats kept anchored at Naha port in those days.

Sulphur brings great benefit to the Ryukyu Kingdom

A Ryukyu Administration dept. was established at the Kokushikan, National University of China. This dept. extends a warm welcome to Ryukyu exchange students, above and beyond that which is extended to students from other countries. Also, the Meiofu gave advantageous privileges to Ryukyu- kokushi as decided by the emperor himself.

In addition small Ryukyu horses were sent across the sea to China together with the sulphur tributes. At that time Chinese war horses were gathered from a Northern horse riding tribe who had many thoroughbred-like horses that could run at high speeds. If a Ryukyu horse was crossbred with these horses then the result would be a slow horse that would be no use as a war horse.

As a means of carrying the sulphur packed like bricks the Ryukyu kingdom shipped the small but powerful Ryukyu horses to be used as a kind of truck. The Ryukyu horses carried the sulphur from Fukushu to Beijing and were left behind in China where it is said they were used as riding horses on Ming's Great wall of China. Sulphur brought great benefit to the Ryukyu Kingdom.

When was Shuri castle built and who built it?

Shuri castle, the symbol of the Ryukyu kingdom, is surrounded by numerous mysteries. For example, when was Shuri castle built and who built it? And why was the castle built facing due West? The reason for this is not well understood. Also, it is said that Shuri castle was not a castle constructed for military purposes. The reason being that there was no provision for food storage within the castle grounds in the event that the castle may be surrounded and cut off by an enemy during a siege. Why would this have been the case?

What could have been the purpose for which Shuri castle was built? In addition, how were the palace construction supports calculated and what was the architectural know-how and craft techniques? Also why was there an artificial moat purposely arranged in the shape of a dragon? Someone must have had great knowledge of the latest techniques for that time.

Many more mysteries and questions from the prehistoric and ancient Ryukyu times continue to appear. Since there is no formal record of these matters these mysteries continue to remain unclear even today. However, there is one method by which these questions can be solved. That is to look outside of the Ryukyu kingdom

Four key words for solving the mysteries of Ryukyu history

If the same era of history of surrounding countries, such as China, Korea, Japan and South East Asian countries, is looked at very closely then the general outline of Ryukyu history can be surmised. This is because within the history of each of those surrounding countries an important factor for solving Ryukyu mysteries can be found.

Basically there are four important key words; the Japan current, seasonal wind, Wako and Kakkajin. When the Ryukyu mysteries are overlapped with these four keywords many things become apparent. These four words are said to be the keys for solving the mysteries of Ryukyu history.

The roots of Uchinanchu which we do not even understand now. The God of Niraikanai. Japan's oldest farm and the discovery of China's ancient coins. The Ryukyu Kingdom's South East Asian trading system. The Yayoi period shellfish bracelet mystery. The connection with Nanso-Heike, etc., etc. All these mysteries can be solved using two of the key words; the Japan current and seasonal wind.

Broadening the perspective on Asian history

History is said to be easily understood when you take a broad overview from above. Mr. Ryotaro Shiba (an author) speaks of writing historical novels based on a 'bird's eye' perspective of historical events. Accordingly Ryukyu history should not be viewed exclusively from the sole perspective of the Ryukyu island chain, rather it is necessary to consider East Asia, South Asia and the South Pacific regions too.

The Indonesian peninsula, Chinese continent, Korean peninsula and the East China Sea bank up around the Japan islands, moreover along that projected line are the Ryukyu islands, the island of Taiwan and South East Asia, plus further on towards the South Pacific there is the Oceania region, Micronesia, Polynesia, Melanesia etc.

This vast region has been bound by powerful forces of nature; the Japan current and seasonal wind,for tens of thousands of years. So when these factors are also considered a new perspective on Ryukyu history comes into being.

There are many mechanics of the the Japan current of which we are ignorant even today. Three hundred million years have passed since the seas appeared on Earth's surface and it is believed that the flow of the present day currents was formed about thirty thousand years ago. Naha's Yamashita Dokutsu people (32,000 yrs ago) and Kosen people (28,000 yrs ago) where present in Okinawa during the prehistoric era. It is believed that Southern China was connected by land and that these people crossed over on foot.

Mechanics of the Japan current

The Japan current has existed since that early time. It occurs in the Northern equatorial sea quite close to the equator. The sea water is warmed by the direct rays of the sun and rises to the surface to become a warm water zone. The width of the zone is about 1,500 km which is about the same distance as from Tokyo to Naha. The depth is about seven hundred meters and the zone moves from East to West in the opposite direction of the rotation of the Earth. The warm water zone heads due West until it collides with the Philippine continental shelf where it divides into two separate Northern and Southern streams. The Northern stream becomes an ocean current known as the Japan current. The Japan current passes through the Luzon Strait between the Philippines and Taiwan and collides with Kantong Province, Fukken Province in south part of Yangtze River, China where part of it makes a large detour to the East.

Another stream of the current goes North along the strait between Taiwan and Yonaguni Island for one hundred and thirty kilometers at a speed of five kilometers per hour. This stream and the one which detoured near China unite and run together north of Taiwan. Running together these waters have even more power and advance vertically northward like the East China Sea.

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