The Early Castles

The remains of the earliest known castle in Japan can be found at the Yoshinogari Excavation in northwest Kyushu. Dating back to the Yayoi Period (300 BC - 250 AD), While it can hardly be called a castle in the traditional sense, many of the castle elements familiar to us today can be seen in a more primitive form at Yoshinogari: fences, towers, storehouses, and moats. Also found in 400,000 square meter site were the remains of bodies injured by arrows and stone swords - a clear indication of the battles which must have taken place at this site almost 2,000 years ago.

It was around the same time of this village that rice farming had come to Japan from the mainland of Asia. With it came the emergence of a social heirarchy; soon, early Japan was beginning to organize herself into clans around the wealthiest landowners. By around the 5th century, the balance of power had organized to the point where all of 'civilized' Japan was under one central rule. While the emporer was technically the ruler, true political power lay in the hands of the largest clans. This time period from about 400 AD to 710 AD is generally known as the Yamato Period.

The Yamato Period

Sometime in the 4th Century the Yamato extended their rule into Kudara (what is now southern Korea), but were later forced out by the Chinese. They then spent over a century trying to reestablish a foothold on the peninsula, but in 663 they suffered a great loss at the battle of Hakusukinoe and were driven out for good. The Kudara were allies with the Yamato during this battle, and many of them were also exiled to Japan.

Every cloud, it seems, has a silver lining. The new Korean immigrants brought with them experience in castle building, which led to new variations in caslte design. For example, Mizuki, Ohono, and Kii castles are well known as Korean-style castles. These castles were built to defend dazaifu (government offices) from the same Chinese forces which had beaten the Japanese off of the Korean peninsula. Takayasu, Yashima, and Kaneda castles are also well known as Korean-style mountain castles. These mountain castles first appeared late in the 7th century, and are very different from the mountain castles built later on in the Heian Period. These castles, built by the Kudura, are formed to surround the surrounding mountain valley with huge walls made of earth and/or stones. This is virtually the same structure as the castles found in in Korea from the same time period.

In 694 the capital of Japan moved to Fujiwara, and in 710 moved again to Heiji. The castles at both of these capitals were imitations of the Chinese castles such as the ones at Chyoahn (formerly a capital of China) and Rakuyou. Normally these castles were surrounded by high strong walls called rajyou, but the small Japanese rajyou were rather like ornaments, compared with the massive walls of their Chinese counterparts. Ancient Japanese castles were not being made for defense.

The Heian Period

The Heian Period can be considered the start of the 'Middle Ages' in Japan. A newly imposed tax system caused many poor farmers to sell their lands and become tenants of more successful land owners. This allowed the largest landowners to gain wealth and political influence, at the expense of the central government. For most of this era the government was controlled by members of the Fujiwara family, through intermarriage with the Imperial family and clever political maneuvering. However, this often led to inqualified men holding important positions, which further weakened the effectiveness of the government. Soon, with increasing and uncontrolled civil unrest, many landowners began hiring samurai to protect their properties. Thus began the seeds of military rule in Japan.

Castles were built at a greater rate in this period than ever before, but their size and structure were simpler than earlier ones, and there is still a great difference between Heian castles and the 'modern' castles which were to come later. The majority of the castle owners at this time were samurai whose positions were comparatively inferior to later castle lords. Most of these castles had less troops (about a dozen or so), and most were mountaintop castles (yamajiro). These castles were mainly built as a place to flee to in case of emergency. Yamajiro were not convenient to live in, so the owners usually lived at separate locations.

The mountain castles were built by heaping stones along the top of the mountain and placing soil forts at important points. They had partly built ishigaki, which were not strong enough for a real defense; they mostly served a decorative purpose. The main difference between castles of this period and modern castles is that these castles did not have tenshu (main keeps) or any surrounding castle towns.