Forest for Shock and Awe: Ishigakiyama Ichiyajo Castle 石垣山一夜城

This year, I have met sandy Hoei Scoria in Tanzawa Mountains (; my post on July 19). Super-typhoons brought lots of landslides in Yadoriki Water Source Forest やどりき水源林 (; on November 22). There was an encounter about the birth of Shinsei Lake 震生湖 in Hadano City by Great Kanto Earthquake (; on November 15). The ground of Kanagawa Prefecture we stand is fascinating. It’s created by plate tectonics and volcanic activities continuing for … billions of years? Our earth is far bigger than human activities ... people can at least utilize such planetary conditions to survive, just like plants and the other creatures dwelling in forests. Some of human activities become “historical” monuments. Today and next week, I tell you my adventure with one of the remnants of Japanese history in Kanagawa’s soil and forest. Recently, I visited the ruin of Ishigakiyama Ichiyajo Castle 石垣山一夜城 in Odawara City 小田原市. This castle was built thanks to forests and geology of Kanagawa Prefecture. The event with this castle could be the defining reason why Tokyo is the capital city of present-day Japan. Let me explain.

The 14^th and 15^th centuries were the era of civil war in Japanese history. Many warlords struggled for hegemony of this archipelago. By 1590 there were three samurai chiefs aiming for the top. One is Toyotomi Hideyoshi 豊臣秀吉 who was the top dog at that time and built the gorgeous Osaka Castle 大阪城 full of golden ornament. Another was Tokugawa Ieyasu 徳川家康 who later built Edo, aka Tokyo, but still in 1590 stayed low biding his time. The third was the lord of Odawara, Hojo Ujimasa 北条氏政. Ujimasa was the last samurai chieftain who did not bow his head to Hideyoshi. So, in 1590 Hideyoshi ordered the rest of the warlords who declared loyalty to him, including Ieyasu, to gather around Odawara City to besiege. The total number of troops Hideyoshi mobilized was about 220,000, including navy fleets in Sagami Bay 相模湾. As of the first week of December 2019, the total population of Odawara City (with rural areas) is about 190,000. Please imagine the situation when able-bodied army and navy larger than your population of kids and elderly people surround you. Yet, Hojo Clan did not surrender easily.

Toyotomi Hideyoshi.
 The route I introduce you this week and next has
a series of panels describing the historical characters
 who supported Toyotomi Hideyoshi,
 and Hideyoshi himself, of course,
 during the War of Odawara.

For one thing, the House of Hojo was loved by the industrious people in Odawara as a good lord. They supported Hojo family. Moreover, the City of Odawara and Odawara Castle 小田原城 were designed to be resilient under such condition. Hideyoshi thought it would have been a huge waste for future economic development to destroy such a well-organized infrastructure. He concocted a psychological ploy applying more pressure on Ujimasa in order to obtain the entire city intact, i.e., “Shock and Awe” in the 16^th century, Japanese style. Hideyoshi built the most technologically sophisticated castle in 80 days with 30,000-40,000 engineering brigade on a hill 3km west from Odawara Castle. The trick was, during the construction Hideyoshi kept a forest of large trees obstructing the view of the hilltop from Odawara Castle. When the structure was ready, he ordered to deforest the area in one night. On 26 June 1590, after one sleepless night of battle cries of enemies, Ujimasa found his beloved castle and city were watched down by a shining castle built in a way he had never seen before. On July 5^th, Ujinao 氏直, the heir of Ujimasa and a son-in-law of Ieyasu, sent a messenger of surrender to Hideyoshi. Ujimasa was ordered Harakiri on July 11^th, and Ujinao died of illness in November. Hideyoshi became the top of the tops of Japan. Then, very interestingly, he regarded such a barbaric place far from Kyoto 京都 and Osaka 大阪 was not worth for his family to govern. He gave almost all the territory of Hojo Clan to Ieyasu.

The view of the downtown of Odawara City from the hill of Ichiyajo Castle.
 The yellow arrow points out Odawara Castle.
 I imagine it was frightening for the people of Odawara at that time,
 to be looked down by lethal enemies so near …

The well-managed place of hardworking people became the foundation of Tokugawa Clan, and its crown jewel, Tokyo 東京. Ieyasu regarded Odawara strategically important place for the defense of Edo (Tokyo) against the enemies approaching from the west of Hakone 箱根 (as he did, yeah). So, he and his successors of Tokugawa Shogunate placed the most reliable vassals to manage Odawara area. Accordingly, the retainers dispatched from Edo remodeled Odawara Castle of Hojo Clan as they liked. The building changed its feature drastically in the process … Last year, after several years of renovation, the castle was reopened for the tourists of the 21^st century. Yap, it is an old architecture so that it needed to update its fireproof system et al. Yet, VERY interestingly, people of Odawara chose to recreate rooms and their interior design according to the data of the Castle of Hojo Clan. People remember, even 400 years later, the days of Hojo Family …

Odawara Castle, Hojo style

Returning to our subject, there remain several historical documents explaining the design of Ichiyajo Castle. In the region north of Hakone, this was the first built on elaborately laid fence with unprocessed natural rocks, called Nozura-zumi 野面積み. By doing so, under rainy and humid Japanese climate, the foundation of the structure became more solid by semi-natural drainage system. The methodology to build the fence in an efficient and quick way was recently devised at that time by civil engineers based in the area of Biwa Lake 琵琶湖, near Kyoto. It was not known in Eastern Japan. Moreover, although its function was basically for war-fortress, the castle had many “elegant” rooms and towers (Yagura 櫓) where Hideyoshi invited lots of emissaries of Emperor and artists from Kyoto, such as Rikyu 千利休, the founder of Japanese tea ceremony. They enjoyed nights of gorgeous parties. Hideyoshi’s consort and the mother of his heir, Lady Yodo 淀の方 stayed in the castle with her troops of ladies in waiting and spent her ordinary days of bling as she was in Osaka or Kyoto. To maintain their high-life, the castle had water system of rock fence, called Ido-kuruwa 井戸曲輪, that could maintain water quality from the well near the top of the hill. It was not only Hojo Family, but also the other warlords who declared their loyalty to Hideyoshi for convenience were awestruck by ostensive and overwhelming wealth and power of Toyotomi Family. It was another objective of this castle.

Nozura-zumi fense.
 Archeological reconstruction is still going on.

Sen-no-Rikyu. The founder of Japanese Tea Ceremony

Lady Yodo

The remain of Ido-kuruwa which is a rare archeological site for Japan,
 maintaining this much of structure more than 400 years later.

After the capitulation of Hojo Clan, Hideyoshi did not give this castle to Ieyasu, but destroyed it and left only its rock fences. Wooooooooooooooow. It’s something only extremely rich and powerful could do … But Planet Earth was greater. The Great Kanto Earthquake of 1923 destroyed the sturdy stone fence, and the collapsed place was covered once again by forests. In 1959, Japanese government registered the place as important archeological artefact. The ruin became a part of Fuji-Hakone-Izu National Park 富士箱根伊豆国立公園. The restoration work continues as of today. Now the area is called Ishigakiyama Castle Historical Park 石垣山一夜城歴史公園 receiving lots of visitors. In 2016, Toshihiko Yoroizuka, a chef trained in Europe, Sheraton and Hilton Hotels, opened one of his restaurants, named Ichiyajo Yoroizuka Farm 一夜城鎧塚ファーム, near the car parking space. The venue serves top-notch European style cuisine and sweets along with local produces. The place is “well” priced and always congested … some say it makes historical place vulgar … Don’t you think it might resonate with the memory how Hideyoshi utilized the place for his purpose? One thing is for sure: their ice cream is 350 yen, and VERY tasty. 😋

In this place, once there were banquet halls et al.
 The small hill over there is thought
 to have had a shining castle tower.

Ichiyajo Yoroizuka Farm. RSVP for Christmas dinner.

The park has an ample parking space.
 Many foreign tourists come here by sightseeing bus.

Next week, I tell you how to hike there and what I’ve found in trees and rocks of the area. The entire itinerary is on paved roads! You can visit there with your town shoes. Please stay tuned. 😉

Ishigakiyama Castle Historical Park 石垣山一夜城歴史公園

1383-12 Hayakawa, Odawara City, 250-0021神奈川県小田原市早川1383-12