I came across this website today called Stoneworld.com that has an interesting story regarding the construction of replica Japanese castle stone ramparts at a park here in California. The stone ramparts were constructed in January of this year in Ventura, a small city of about 100,000 people 2 hours north of Los Angeles. Master stonemasons came from Japan to California to supervise their North American counterparts in the construction of a traditional Japanese structure — castle ramparts — using ancient but still viable techniques.
They used nearly 400 tons of sandstone, a very common stone here in Southern California. This is different from the type of stone used in castle building in Japan which I believe is granite. If someone knows for sure the specific type of stone used in Japan, please let me know. The Japanese stonemasons used a traditional method of splitting the stones called mame-ya.
The article talks about Auchi castle, the magnificent castle built by the great warlord Oda Nobunaga at the height of his power. Azuchi was was of the grandest castles in Japanese history, rivaling or exceeding Osaka or Edo castle in grandeur. Oda Nobunaga is infamous for his destruction of the Buddhist temple complex on Mt. Hiei. The warrior monks from Mt. Hiei had long been a dangerous thorn in the side of Nobunaga. In 1571 Nobunaga dealt with the warrior monks in a most brutal way, laying waste to everything and everyone on Mt. Hiei, killing everyone who did not escape. However, Nobunaga did find something he truly appreciated on Mt. Hiei, very well built stone walls. The walls were apparently built by a community of stonemasons who lived at the foot of Mt. Hiei and known as the Anoh. The Anoh were originally brought from Korea to Japan in the 6th century and later it was the Anoh stonemasons who helped construct Nobunaga's Azuchi castle in 1579. Unfortunately for Nobunaga, he would be dead by 1582 and his beautiful castle burned to the ground after being completed only three years prior.
According the Stone World article, there still lives a family at the foot of Mt. Hiei who carry on the traditional way of stone working. Jyunji and Suminori Awata are father and son 14th and 15th generation stonemasons. The Awatas were even commissioned to help stabilize the stone rampart remains of Azuchi Castle according to the article. It was the Awata Construction Company that was incentive for the Ventura California project. The article has additional interesting information about the Awata's and their trade.