関東地方～Kanto Region – ページ 2 – 日本200名城バイリンガル (Japan's top 200 castles and ruins)

23.Odawara Castle Part2

I think that the bast way to feel what Odawara Castle was during the Sengoku Period, would be to wak the So-gamae structure. Therefore, this article will show you how to walk around the So-gamae in the current Odawara City.

Features

Rare Remaining So-Gamae structures on Plain Area

Unfortunately, there are only a few remaining structures of So-gamae on the plain city area. First of all, it might y be better to walk the old Tokaido Road to the east. The starting point would be Matsubara Shrine, or a rest station called “Odawarajuku-Nariwai-Koryukan”, which are located at the center of the old transportation hub of Odawara.

It would be more comfortable to go on Kamaboko Street, where there are many traditional Japanese fish cake (which is called Kamaboko) shops are located, which is also similar to the route of the old Tokaido Road during the Sengoku Period. If you walk along the street for a while, you will eventually reach Hojo Inari Shrine. The shrine was built by the Hojo Clan and at the southeast corner of the So-gamae structure.

If you turn left to the north of the shrine, you will soon find the ruins of Edoguchi-mitsuke (which means the gate to Edo). The gate was the eastern entrance of Odawara Transportation Hub during the Edo Period. It was also the Sannoguchi Gate of the So-gamae structure earlier on. Therefore, the partitions of the gate were used until the end of the Edo Period.

In addition, there is also Sanno Shrine, which is little far from the gate ruins, which was a defensive position of the Hojo Clan outside the So-mgamae during the Battle of Odawara. The only direct fighting during the battle happened at this site.

The ground of the shrine looks like a defensive position

If you go on the path beside the gate ruins, you will eventually arrive at one of the few remaining structures of So-Gamae in the city area. It is called, Renjoin Temple Earthen Walls, which is about 100m long and about 3m high. It was originally set with a moat and more defensive than this single unit. You will see a large dent on the walls, which was caused by the Odawara air raid in 1945 during World War II. The ruins had a long history through the multiple periods.

Remaining Structures on the Hill Areas

An easy way to the So-gamae structure on the hill area is to go on the opposite street of a park, called “Medaka-no-gakko”. The street will go up on Yatsu Hill, one of the hill areas behind the Odawara city area. You will eventually find the ruins of Shiroshita-Haridashi. Haridashi refers to the overhanging part of the So-gamae structure. The defenders could have lookout point of the attackers and could counterattack the side from the site. The remaining structure is the base of the overhanging part. That’s why the line forms a right angle.

You can also look around the remaining dry moats along the hill. However, most of them are currently farms now, where visitors are not allowed to enter.

If you continue to go along the street for a while, you will eventually encounter a three-way intersection. Turn right at the intersection, then you will be able to travel on the So-gamae structure easily.

After a while, you will be at Yamanokami-Horikiri. Horikiri refers to a ditch separating a hill in order to avoid the enemies from attacking through the hill. If you go to the bottom edge of the Horikiri, you will find the dry moat of the So-gamae structure touching the Horikiri at right angles. However, the moat is much deeper than the Horikiri. That means the enemies that fell inside the moat, would not be able to invade the Horikiri easily.

Looking at the moat of the So-gamae structure from the edge of the Horikiri ditch

Looking up the earthen walls of the So-gamae structure and the ditch from the bottom of the moats

Next comes Inari-mori (which is the town name). At this site, the earthen walls and dry moats of the So-gamae makes a dent inwards along the natural terrain. The outside of the depression looks like an isolated island. The Hojo Clan also built earthen walls on the island in part to not allow enemies to stay there. This site is one of the most intact parts of the So-gamae structure. The moats managed to keep their original conditions of about 10m deep and over 50-degree slant. This is probably why the visitors are kept out from the moats by ropes and poles.

Large Ditchies of Komine Okane-no-dai, Highlight of So-gamae Structure

The northern part of Odawara City is surrounded by the three hill areas: Hachimanyama, Tenjinyama, and Yatsu. Komine Okane-no-dai hill is part of the Hachimanyama hill area and the highest among the areas. Therefore, the hill was the most important spot for the Hojo Clan in terms of protecting Odawara Castle from invasion. The clan eventually separated the hill by building three ditches. If you walk from the Inarimori Ruins along the So-gamae structure, you will reach the intersection to the three ditches. If you turn right, you will be at the western ditch, left to the eastern ditch, or if you keep going straight, it will lead to the central one.

The western ditch is at the outermost area on the hill, which was originally over 200m long, but is now only 150m long. It was built just before the Battle of Odawara. The ditch seems to get shallower and gentler compared to the original condition. However, if you look at the bottom of it, you can still see something that resembles partitions, which may be the traces of the Shoji-bori system. The edge of the ditch is still connected to the moat of the So-gamae structure.

Next comes the central ditch, which was built at the same time as the western one. The bottom of the ditch is now used as a modern road. You can still see some of the earthen walls around it remaining. A connecting road between this ditch and the eastern ditch still exists.

You will finally arrive at the eastern ditch, which has been developed as a park. You can easily walk the bottom of it. This ditch is the most intact one among the three ditches, which is 280m long and 25 to 30m wide, the same as the original conditions. It is currently 8 to 10m deep, but it was originally about 12m with the Shoji-bori system. Its slant is about 50 degrees, which may be the same as original one, too. The bottom of the ditch is not straight but rather curved, which made it difficult for enemies to walk through smoothly.

The ditch seen from its earthen walls around

Where is the goal of the So-gamae?

You will eventually go down on the hill to the New Moats and Earthen Walls of the Outer Third Enclosure. This place is where Ujimasa Hojo launched the constructions of the So-gamae structure. You can see a great view to the west from there, including Ishigakiyama Mountain where Hideyoshi Toyotomi built his Ishigakiyama Castle during the Battle of Odawara Castle. There is another interesting story where the Hojo side was very surprised to see the completion of Ishigakiyama Castle after all the trees around were cut down, called “Ichiyajo” which means “one night castle” (a castle that only took one night to build). However, the story may be doubtful because the castle ruins can clearly be seen from the site. In addition, please be mindful that the site closes at 3:00 PM, which is much earlier than other historical sites.

The New Moats and Earthen Walls of Outer Third Enclosure

You need to check out the opening hours of the site

You will next walk down to the Tenjinyama hill area. This area also has walls of the So-gamae, called the Earthen Walls, at the west of Denjoji Temple. The walls are located in front of the elevated railways of the Shinkansen (bullet train) and used as a graveyard. If you look up the site from below, you will realize this structure uses natural terrain as well.

After returning to the city area, you should also check out Hayakawa-guchi Ruins (Guchi means entrance or route), one of the few remaining items of the So-gamae structure on the plain area. The Hayakawa-guchi entrance was the front line to the west, where the Toyotomi troops attacked from. Therefore, the entrance was fortified heavily by doubled earthen walls and moats. If you enter the ruins, which have been developed as a park, you will eventually find that the park is sandwiched between the remaining doubled walls.

Other than that, you will be able to find other remaining earthen walls of the So-gamae structure, which are used as the bases of the modern residences along the seaside. If you find one of them, you will be able to understand that these structures were built on such a place and are still intact for the modern facilities to use. This will conclude the tour of the So-gamae structure.

This base of the modern residence uses the earthen walls of the So-gamae structure (its stone walls were probably added later on)

To be continued in “Odawara Castle Part3”

20.佐倉城　その１

佐倉城は、千葉県佐倉市にあった城でした。この城は、佐倉藩の本拠地として江戸時代に築かれ、現在の佐倉市につながっていきます。ところで、佐倉周辺の地域には、戦国時代までは多くの城があり、歴史上重要なものもありました。

立地と歴史

佐倉城は、千葉県佐倉市にあった城でした。この城は、佐倉藩の本拠地として江戸時代に築かれ、現在の佐倉市につながっていきます。ところで、佐倉周辺の地域には、戦国時代までは多くの城があり、歴史上重要なものもありました。例えば、佐倉市西部には、臼井城があり、１５６６年（永禄９年）に有名な臼井城の戦いが起こりました。関東地方の制覇を狙う上杉謙信勢が、北条氏を後ろ盾とした千葉氏の家臣・原胤貞が立て籠もる臼井城を攻撃しましたが、大損害を被り撤退したことで、失敗に終わります。この戦いは謙信の数少ない敗北の一つとされ、その後の彼の関東経営は後退を余儀なくされました。その千葉氏の本拠地・本佐倉城（もとさくらじょう）は、佐倉市の東境周辺にありました。「本佐倉城」とは戦国時代末期からの呼び名（天正１８年５月２日付浅野長吉・木村一連署添状が初見）なので、元来こちらの方が「佐倉城」だったのでしょう。現在の佐倉城を語るには、千葉氏の「本佐倉城」から始めた方が分かりやすいと思いますので、この記事では「佐倉城前史」の記述から始めます。

佐倉城前史

千葉氏は、平安時代後期以来、下総国（ほぼ千葉県北部）周辺を支配する豪族でした。頼朝の鎌倉幕府創業のときに貢献した千葉常胤（ちばつねたね）が有名です。千葉氏は各地に一族を送り込み反映しますが、惣領家は現在の千葉市にあった亥鼻城（いのはなじょう、別名千葉城）を長い間、本拠地としていました。１４５５年１月（享徳３年１２月）に享徳の乱が起こると、関東地方が戦国時代に突入します。関東公方（後の古河公方）の足利氏と、関東管領の上杉氏が戦うようになり、千葉氏も巻き込まれました。その混乱の中で亥鼻城が荒廃したため、千葉氏は新たな本拠地を築きました。それが本佐倉城で、遅くとも１４８４年（文明１６年）には存在していました（下記補足１）。この城は、下総台地が入り組んだ丘の上にあり、当時は周りを印旛沼や湿地帯に囲まれていました。以前の城よりは防御力に優れていたのです。また、城の南側に下総街道が通り、印旛沼は霞ケ浦に通じ、「香取海（かとりのうみ）とも呼ばれ、水上交通にも利用できたため、同盟関係にあった古河公方とも連絡が容易な立地でした。

（補足１）文明十六年甲辰六月三日佐倉の地を取らせらる。庚戌六月八日市の立て初め、同八月十二日御町の立て初め也。二十四世孝胤の御代とぞ。（「千学集抜粋」）

しかし１６世紀（１５００年代）になると、状況が変わってきます。北条氏が、相模国（神奈川県）から関東全域に勢力を伸ばしてきたのです。千葉氏の内部でも対応を巡って争いがありましたが、重臣の原氏を中心に北条氏に傾きます。房総半島では里見氏が勢力を伸ばしていて、上杉謙信と同盟していました。そういう状況の中で、起こったのが臼井城の戦いでした。謙信は関東地方の諸将に動員をかけ、北条氏の本拠・小田原城を囲んだ時以上の軍勢だったとも言われますが、城の攻略に失敗したのです。その城の城主、原胤貞は、重臣の原氏の当主だったので、その勢力はより高まったことでしょう。千葉氏の本拠地・本佐倉城はそのおかげで無事だったのです。一方、惣領の千葉氏には本拠地を移す動きもありました。その候補地が、下総台地の西端の「鹿島台」と呼ばれた場所でした。後に佐倉城が築かれるところで、本佐倉城と臼井城の中間地点に当たりました。臼井城の戦いの１０年以上前の当主・千葉親胤（ちかたね）が築城を始めたと伝わります（下記補足２）。しかし１５５３年（弘治３年）に家臣に殺され、頓挫しました。

（補足２）親胤或時新城を築きて之に居らんと欲し、近隣の南方に土木工事を興して、既に竣成に至りしも、未だ果さざる事ありて、暫く鹿島大与を此所に居らしむ。即ち此の城を名づけて鹿島の新城といひ、旧城を本佐倉城と稱し、代々の菩提所海隣寺を新城の傍に移せり。（「千葉伝考記・巻四」）

城の位置

上杉謙信肖像画、上杉神社蔵 (licensed under Public Domain via Wikimedia Commons)

千葉親胤肖像画、久保神社蔵 *(licensed under Public Domain via Wikimedia Commons)*

１６世紀末期になると、北条氏が下総国の支配を強めるため、千葉氏の内部に介入してきます。当主・千葉邦胤（くにたね）の正室は北条氏政の娘（芳桂院（ほうけいいん））でした。そして北条氏の意向として、鹿島城（鹿島台の城）の築城を再開しますが、１５８５年（天正１３年）に邦胤まで家臣に殺されてしまい、また頓挫したと言われています。その後北条氏政が佐倉の直接支配に乗り出し、邦胤と芳桂院の娘（東（とう））の婿として、氏政の息子・直重（なおしげ）を千葉氏の後継者としました。そして直重夫妻の居城として、また鹿島城の築城を行ったと伝わります（下記補足３）。

（補足３）氏政の末子を申受け、十二歳の姫に娶せ申し、「家督相続すべし」とて、天正十三年十一月、本佐倉は城地狭きため、神（鹿）島山今の佐倉へ、城地取立て、北条の威勢にて（中略）十一月廿二日に企て、廿三日普請始め、十二月十二日に屋形塀等大半出来、同十五日には十二歳の姫君并に母君御移し申し、其の後氏政の末子を小田原の本家へ引取られ、実子亀若丸を重胤と号し、佐倉城へ引取可申之処、俄に小田原陣始まり、小田原北条氏政の味方して籠城し給ふ。其の時亀若丸六歳なり（「妙見実録千集記」）

北条氏政肖像画、小田原城蔵 (licensed under Public Domain via Wikimedia Commons)

これら一連の鹿島城伝承の検証は困難です。後の佐倉城と場所が重なってしまっているからです。中世の空堀跡が見つかっていることから、少なくともここに築城しようとしたことは確かでしょう。鹿島へ本拠地を移転しようとしていたならば、その理由にの一つには本佐倉城よりも敷地が広かったことが挙げられるでしょう。それから、北条氏の立場からは、西の方角への防御力に優れた鹿島城は、豊臣軍の西からの攻撃に備えるためとは言えないでしょうか。直重は、１５９０年（天正１０年）の小田原合戦のとき、小田原城での籠城を命じられました。千葉氏は邦胤のもう一人の息子（側室の子）重胤（しげたね）が最後の当主となりますが、北条氏の滅亡とともに改易となってしまいました。重胤も小田原城に籠城したという記録があります（「総葉概録」など）。

土井利勝による佐倉城築城

小田原合戦の後、関東地方には徳川家康が入り、佐倉地域には一族（武田信吉、松平忠輝）や家臣（酒井家次など）が配置されますが、短期間で入れ替わったため、拠点整備には至りませんでした。１６１０年（慶長１５年）家康は、土井利勝を本佐倉城に入れ、旧鹿島城の地に、新城と城下町を建設することを決めました。この新城が佐倉城です。この城には、家康が創設した江戸幕府の本拠地・江戸城の東方を守る役割を課せられました。江戸城が西から攻められたときに、東からバックアップし、将軍の避難場所とするための城だったと言われています。旧鹿島城の地はそれに相応しかったのでしょう。

土井利勝肖像画、正定寺蔵 (licensed under Public Domain via Wikimedia Commons)

その任務を帯びた土井利勝は、徳川家康・秀忠・家光の３代に重臣として仕え、幕府の安定化に貢献しました。利勝は、家康が浜松城主時代の１５７３年（元亀４年）に生まれました。その出自にはいくつか説があります。１つ目は、幕府の系譜書（「寛永諸家系図伝」「寛政重修諸家譜」）によると土居小左衛門利昌の子、２つ目は、幕府の正史「徳川実記」新井白石「藩翰譜」などによる家康の母・於大の方の兄、水野信元の子とするものです（下記補足４）。最後は土井家の「土井系図」で、そこでは何と家康のご落胤としているのです（下記補足５）。

（補足４）利勝實は水野下野守信元の子なり。さる御ゆかりを思召れての事なるべし（「徳川実記」）

（補足５）利勝公　実家康君之御子也　天正元癸酉年三月十八日於遠州浜松御城御誕生号松千代殿

徳川家康肖像画、加納探幽筆、大阪城天守閣蔵 (licensed under Public Domain via Wikimedia Commons)

最近の研究（「藩祖・土井利勝」所収）によると、以下のような見解も出されています。「利勝が家康から賜った水野家の家紋（沢潟紋）入りの短刀があり、それは於大の方が実家から持参したもので、実際には家康の子であることを示すものだった。利勝の孫・利益（とします）が、当時地位が落ちていた土井家の状況を鑑み、自ら信元説（２つ目）を流した。ところが、その後幕府から利勝の生母について問合せがあり、そのときの当主・利里（としさと）が真相を回答し、幕府は公式見解は改めないものの、黙認したので、土井家の系図に残した。」というものです。利勝は７歳にして、家康の子・秀忠の傅役に任命されました。目を懸けられていたことは確かでしょう。そしてそのまま秀忠の側近（老職）となるのです。

土井利益肖像画、正定寺蔵 (licensed under Public Domain via Wikimedia Commons)

関東創業時の家康には、最有力の側近として、本多正信・正純父子と大久保忠世・忠隣父子がいました。ところが、１６１４年（慶長１９年）大久保長安の不正蓄財事件をきっかけに、大久保忠隣が失脚します。家康と正信の没後は、本多正純が抜きん出た形になりましたが、それに対抗したのが秀忠の側近、酒井忠世・土井利勝などでした。１６２２年（元和８年）今度は正純が失脚（改易）しますが、利勝ら側近たちが関与していたとも言われています。決断は将軍・秀忠によるものですが、そのお膳立てが、忠隣のときの意趣返しのように仕組まれていたからです。双方とも反乱を防ぐため、出張した時に言い渡されているのです。利勝は、次の将軍・家光の時代にも、自らが亡くなるまで元老として、家光の側近・松平信綱（川越藩主）、稲葉正勝（小田原藩主）、堀田正盛（後の佐倉藩主）らとともに、幕政に関わりました。やがて老中・若年寄の集団指導体制が確立され、幕府政治が安定していきます。

本多正信肖像画、加賀本多博物館蔵 (licensed under Public Domain via Wikimedia Commons)

大久保忠世肖像画、小田原城蔵 (licensed under Public Domain via Wikimedia Commons)

利勝が幕閣にいた頃は、内部抗争もあり、大物大名改易、一国一城令、参勤交代、御三家創設、鎖国政策など、幕府による統制が進んだ時代だったので、彼には冷酷な権謀術数家とのイメージもあります。しかし一方では、海外を含む情報通（「コックス日記」）であり、実直な人柄でもあったようです（下記補足６）。その利勝が７年かけて作った城が佐倉城なのです。利勝は、１６３３年（寛永１０年）には古河藩に加増移封となり（１４万２千石→１６万２千石）、古河城も大拡張しました。

（補足６）土井大炊殿、いよいよ御出頭にて候、拙老も節々参会申し、別して御意をえ申し候、我等旅宿へも御出候て、しみじみと放（話）申し候、ことのほかおくゆかしき御分別者に見および申し候、両御所様（家康・秀吉）御見立の仁に候あいだ、申しおよばざることに候、今は出頭一人のようにあいみえ申し候、人の申すことをも、こまごまと御聞候、寄特に存じ候ことに候。（金地院崇伝）
私はキャプテン・アダムス（三浦按針）とニールソン君を伴ってオイエン（土井利勝）殿のところへ赴いたが、運良く彼が彼の自宅の前を通りに出たところで出くわして、閣下に皇帝（秀忠）から我々のための我々の事務処理を受けて欲しいと願ったところ、彼はすぐにも処理すると約束し、我々がそんな長く滞在していることを恥ずかしく思うとの由で、しかもその上彼が私には感謝していると私に告げた。（「コックス日記」１６１８年１１月４日）

佐倉城の特徴

広い台地上に築かれた佐倉城には、いくつも特徴がありました。まずは、その台地の自然の地形を巧みに利用したことでしょう。台地は麓から約２０メートルの高さがあり、南と西を高崎川と鹿島川に囲まれ、自然の要害となっていました。加えて、台地を水堀でも囲みました。台地上の西の先端に本丸を構え、二の丸・三の丸・惣曲輪などを周りに配置しました。そして、東に向かって巨大な大手門や空堀などを作り、防衛体制を固めたのです。城下町や武家屋敷は、その更に東側の台地上に建設されました。成田街道もその城下町を通るように設定されました。つまり城と町を丸ごと、台地の上に作ってしまったわけです。

次に挙げられるは、石垣を使わない土造りの城だったことでしょう（土塁、空堀、切岸など）。小田原合戦のとき秀吉が初めて、関東地方に本格的な総石垣造りの城を作りました（石垣山城）。それ以来、関東地方にも石垣を使った城が多く現れます（江戸城など）。しかし佐倉城は、関東地方ならではの、土造りの城のスタイルを継承していました。同様の例としては、川越城、宇都宮城があります。一方で、城の防衛システムには、当時最新の仕組みが取り入れられていました。例えば、三の丸の門の前には「馬出し」と呼ばれる突出した防衛陣地が２ヶ所設けられていました。また、三の丸の周りの惣曲輪（東惣曲輪と椎木曲輪）は広大で、武家屋敷の他、練兵場に用いられ、多くの兵が駐留できるようになっていました。更には、台地の斜面には帯曲輪があって兵の移動が容易であり、その先の台地の西と東に出丸もあって、防衛の拠点になっていました。

３つ目は城の建物についてです。本丸には高さ約２２メートルの３層４階（＋地下１階）の天守が建てられました。築城時期から考えると、佐倉城だからこそ許されたのでしょう。江戸城の三重櫓を移築したものとも言われています。江戸後期に盗賊による失火で焼失したため詳細は不明ですが、土井利勝が古河に移ってから建てた御三階櫓とほとんどサイズが一緒のため、似た外観だったと考えられています。本丸には他に、銅櫓と角櫓がありました。内部には本丸御殿（御屋形）がありましたが、徳川家康が休息して以来、通常は使われませんでした。藩主は代わりに通常は二の丸御殿（対面所）を使っていました。幕末になり老朽化すると、三の丸外に新たに御殿が建てられました。

土井利勝が古河に移った後は、譜代大名が頻繁に入れ替わり、佐倉藩主（城主）となりました。
利勝以後の藩主または大名家を記載します。
・土井利勝（1610年〜）：老中、後に大老
・石川忠総（1633年〜）
・形原松平家２代（1635年〜）
・堀田家２代（1642年〜）：正盛が老中・将軍家光に殉死、正信が無断帰国で改易
・（大給）松平乗久（1661年〜）
・大久保忠朝（1678年〜）：老中首座
・戸田家２代（1686年〜）：忠昌が老中、忠真が寺社奉行・後に老中
・稲葉家２代（1701年〜）：正往が老中
・大給松平家２代（1723年〜）：乗邑が老中首座、
・堀田家６代（1746年〜）：正亮（老中首座）、正順（京都所司代）、正睦（老中首座）
幕府の幹部、老中を多く輩出した藩であるため、佐倉城は「老中の城」とも呼ばれています。
江戸時代後半からは安定し、堀田家が幕末まで、藩主を務めました。
その中で、幕末に藩政改革や幕府の老中の職務を通して、開国方針を貫いた堀田正睦（まさよし）を取り上げてみたいと思います。

開国に尽力した堀田正睦と佐倉城

正睦は１８１０年（文化７年）生まれで、３２歳のとき本丸老中となり、幕府中枢のメンバーになりましたが、ときの老中首座・水野忠邦と反りが合わず、２年余りで辞職しました。このとき将軍に直接ものが言える「溜の間」格になったことが、阿部正弘や井伊直弼とのつながりができ、後に老中に再任され、彼の開国の業績につながったという見方があります。

堀田正睦 (licensed under Public Domain via Wikimedia Commons)

正睦は老中になる前から、三の丸御殿に藩士を集め、藩政改革を宣言し、推進していました。その柱は「文武奨励」「兵制改革」「医学奨励」「民政改革」でした。兵制改革については、城中に西洋砲術の練習場を作り、ついには旧来の火縄銃を廃止し、いち早く西洋式の兵制に改めました。また、側近の渡辺弥一兵衛の癰（よう、腫れ物）が蘭方医の治療により完治したことから、西洋医学（蘭学）を導入し、江戸から名医・佐藤泰然を招きました。泰然は佐倉の城下町で佐倉順天堂を設立します（後の順天堂大学病院にもつながります）。佐倉はやがて長崎と並ぶ蘭学の地と称され、正睦もまた「蘭癖」というニックネームが付きます。佐倉の城と町は、正睦の改革の発信基地となったのです。

佐藤泰然 (licensed under Public Domain via Wikimedia Commons)

やがて、ペリーが来航（１８５３年）すると、老中首座の阿部正弘は、広く開国について諮問を行いました。正睦の回答は、当時としては思い切った開国通商論でした（下記補足７）。そのせいなのか、１８５５年（安政２年）彼は突然老中首座に抜擢されました（実権はまだ阿部正弘にあり）。翌年には「外国事務取扱（外交専任老中）」となり、またその翌年には阿部の死により名実ともに幕閣のトップになりました。彼の大仕事の一つが、アメリカ総領事ハリスへの対応（江戸出府問題）と通商条約の交渉でした。正睦は積極的開国派であったので（下記補足８）、ハリスの江戸城での将軍徳川家定への謁見を実現し、日米修好通商条約の交渉を進めました。交渉役には、叩き上げの優秀な官僚（岩瀬忠震・井上清直）を任命しました。内容的には、関税自主権がないなど不平等条約であったり、通貨交換規定が不備であり金が国外に大量流出することになります。しかし、神奈川（横浜）を開港場とするなど評価できる点もありました。

（補足７）彼に堅牢の軍艦これ有り、我が用船は短小軟弱、是彼に及ばざる一ツ。彼は大砲に精しく、我は器機整わず二ツ。彼が兵は強壮戦場を歴、我は治平に習い自ら武備薄く是三ツ。右三ツにて勝算これ無く候間、先ず交易御聞届け十年も相立ち、深く国益に相成らず候わば其節御断り、夫までに武備厳重に致し度候。夫とも国益に候わば其儘然るべきや。（「正睦伝」）

（補足８）怖れ乍ら神祖遠揉の御盛意在らせられ、慶長五年泉州に渡来仕り候阿蘭陀人英吉利人の船、江戸表へ廻され御城に召され、九カ年の遺留をも御許容もこれ有り。（中略）鎖国の法には戻られ難く存じ奉り候間、国初めの御旧例に依らせられ、異邦の御処置首尾全く御変革遊ばされ、其段海内へ御演達これ有り、公平に隣国和親の礼儀を以って、亜国官吏速やかに江戸表へ召され、登城御目見え仰付けられ、神祖遠揉の思召の如く、御懇篤の御処置御座候わば、礼儀は勿論道理も全備仕り候間、彼も是までの意匠を改め、自然感心悦服仕り、却って御益得もこれ有るべきやに存じ奉り候。（「外交関係文書」之十六）

阿部正弘肖像画、福山誠之館蔵 *(licensed under Public Domain via Wikimedia Commons)*

タウンゼント・ハリス *(licensed under Public Domain via Wikimedia Commons)*

条約交渉は終わっても、もっと大変だったのが、幕府内での承認でした。創業時と違い、幕閣トップであっても重大案件は、同僚の老中だけでなく、御三家、溜の間格など関係有力大名に根回しをする運用になっていたのです。前任者の阿部正弘は周りに気を使い、周到に事を進めることに長けていました。一方、正睦は口下手だが意思を込めて淡々とことを進めていくタイプでした。実際、有力大名１８名のうち賛成はわずか４名でした。そこで正睦が考えたのが、これまで必要なかった天皇の勅許を得ることでした。１８５８年（安政５年）正月、正睦は自ら京都に乗り込みますが、勅許獲得は失敗します。孝明天皇の条約拒否の意思が判明したからです（下記補足９）。正睦は将軍に一橋慶喜を推して政局を乗り切るつもりでしたが、それに反対する大老・井伊直弼に罷免されました。

（補足９）日本国中不服ニテハ実ニ大騒動ニ相成候間、夷人願通リニ相成候テハ天下の一大事の上、私の代ヨリ加様の儀ニ相成候テハ後々迄の恥の恥ニ候半ヤ。（「天皇紀」）

井伊直弼肖像画、彦根城博物館蔵 (licensed under Public Domain via Wikimedia Commons)

条約調印は井伊直弼に引き継がれ、正睦は佐倉に戻り隠居し、城の三の丸に松山御殿を建てて過ごしました。亡くなったのは１８６４年（元治元年）でした。明治維新後、城跡は日本陸軍第２連隊（後に第５７連隊）の駐屯地となりました。その任務の一つは、城と同じく、帝都東京の東方の防衛でした。戦後は中心部分が佐倉城址公園となり、惣曲輪の一つ、椎木曲輪には、国立歴史民俗博物館が建てられてました。城の特徴（台地上の広い敷地）が、現在でも生かされていると言えるでしょう。

リンク、参考情報

・佐倉城、まちづくり支援ネットワーク佐倉
・「上総下総千葉一族／丸井敬司著」新人物往来社
・「千葉一族の歴史／鈴木佐編著」戒光祥出版
・「佐倉市史」
・「シリーズ中世関東武士の研究　第十七巻・下総千葉氏／石橋一展編著」戒光祥出版
・「よみがえる日本の城２」学研
・「歴史群像６５号、戦国の城　下総本佐倉城」学研
・「家康と家臣団の城／加藤理文著」角川選書
・「藩祖・土井利勝／早川和見著」Ｋプランニング
・「徳川幕閣／藤野保著」吉川弘文館
・「評伝　堀田正睦／土居良三著」国書刊行会
・「佐倉って何？」佐倉国際交流基金ゼミ資料

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23.Odawara Castle Part1

Odawara was supposed to be the capital of five generations of the Hojo Clan. The city is now supposed to be a popular tourist spot near Hakone hot spring. Odawara Castle first started as a small one in a new post town. The castle eventually grew under the rules of the Hojo Clan to one of the greatest castles during the Sengoku Period. It was finally turned into an important castle at the western edge of the Kanto Region during the Edo Period. The castle was located at the same place through all its life while it changed a lot, which is a very rare case. This article will focus on the history of the castle until the Sengoku Period.

Odawara was supposed to be the main castle for the five generations of the Hojo Clan. The city is now supposed to be a popular tourist spot near Hakone hot spring. Odawara Castle first started as a small one in a new transportation hub. The castle eventually grew under the rules of the Hojo Clan to one of the greatest castles during the Sengoku Period. It was finally turned into an important castle at the western edge of the Kanto Region during the Edo Period. The castle was located at the same place through all its life while it changed a lot, which is a very rare case. This article will focus on the history of the castle until the demise of The Hojo Clan during the Sengoku Period.

The current Odawara Castle, this main tower was rebuilt according to that during the Edo Period

Location and History (until Sengoku Period)

Beginning of the Castle and the Appearance of Sozui Ise

In the ancient time, passengers, who went to the Kanto Region from western Japan, didn’t often use the Hakone Route, but used the Ashigara Route instead. However, they eventually used the Hakone Route when some shrines near the route became more popular. Odawara was first formed as a transportation hub for the passengers not later than the 14th Century. On the other hand, Odawara Castle was thought to be built in the middle of the 15th Century. The Omori Clan, the first lord of the castle, built it in order to collect taxes from the passengers. For this reason, the castle was still small during its early stage.

The location of the castle

As for the location of the castle, it was said that it was first situated at Hachimanyama old enclosure, which is the north of the current Odawara Castle, and further away from the transportation hub. Considering the purpose of the castle, it may have been at the same place as the current one, or at Tenjinyama Hill, closer to the town.

In the beginning of the Sengoku Period, a man named Sozui Ise, became one of the biggest heroes at that time, and later would become a legend. According to the legend, he started only as a Ronin, but eventually became a great warlord, through his own excellent talent. This has been recognized as a big success story of “Gekokujo” which means “giant killer”. However, in recent studies, it was discovered that he was originally a shogunal military guard called Moritoki Ise. He went to Sunpu, which is the current Shizuoka City, to help his sister who was in a dispute about the succession. She was the wife of the Imagawa Clan’s previous lord and wanted her son to be the successor but had to compete with another candidate.

A copy of the portrait of Sozui Ise, owned by Odawara Castle (licensed under Public Domain via Wikimedia Commons)

Sozui (Moritoki) succeeded in the son’s victory. He got Kokokuji Castle as an award of his contribution, which was the beginning of his real success story. The legend also says that Sozui drove the Omori Clan, which was the lord family of Odawara Castle, out from the castle, by tactics known as “Kagyu-no-kei”. Kagyu-no-kei refers to attacking enemies’ bases by using cows with lit torches on their horns. It was said that the statics had been done since the start of ancient China. However, the recent studies argue that it’s not that simple. According to a historical record, Sozui’s brother and the Omori Clan were actually on the same side at Odawara Castle and were defeated by the Uesugi Clan. Historians speculate that Sozui got Odawara Castle when they became enemies, or the castle was damaged because of a huge earthquake around 1500. Sozui was probably not only a hero, but also a practical man and a good negotiator. The castle was still a branch castle even after Sozui got it.

The statue of Sozui at Odawara Station, attacking by Kagyu-no-kei

Improvement of the Castle by Ujitsuna and Ujiyasu Hojo

Sozui’s successor was his son, Ujitsuna Hojo, who was the second generation of the Hojo Clan. However, Ujitsuna was the person who changed his family name from Ise to Hojo. Therefore, Sozui Ise’s well-known alternate name Soun Hojo did not exist while he was alive. Soun was his Dharma name (this is the name given after the person dies). The reason for the change of the family name would be to go against the authority of the Uesugi Clan, the Hojo’s enemy. The Uesugi Clan looked down on the Hojo Clan because they were outlaws from another province. The Hojo Clan needed to improve their own authority in order to attract the local lords by using their new family name. “Hojo” had been the family name of the vice-Shoguns during the Kamakura Shogunate. Ujitsuna also moved his clan’s home to Odawara Castle.

The portrait of Ujitsuna Hojo, owned by Odawara Castle (licensed under Public Domain via Wikimedia Commons)

Ujitsuna’s son, Ujiyasu Hojo was the third generation of the clan. He managed to increase the clan’s territories in the southern Kanto Region, particularly after the victory of the battle of Kawagoe Castle against the Uesugi Clan in 1546. Odawara Castle and its town were becoming the center of the region. The original small transportation hub was turned into the castle town, being as large as that during the Edo Period. The Odawara Water Supply System was installed in the castle and the town. It is said to be one of the earliest water supply systems in Japan. As for the castle itself, the main portion of the castle was built, such as the current main and second enclosures. A priest, who visited Odawara Castle in 1551, recorded that there was a large pond surrounding the castle in three different directions. Part of the pond remains as the moat of the current second enclosure.

A copy of the portrait of Ujiyasu Hojo, owned by Odawara Castle (licensed under Public Domain via Wikimedia Commons)

The moat of the current second enclosure

The first big crisis happened to Odawara Castle in 1561. Kenshin Uesugi invaded the Kanto Region from his home of Echigo Province, which is currently Nigata Prefecture, in order to revive his clan. Kenshin sieged Odawara Castle with his allies and over 100 thousand soldiers the following February (according to the luna calendar). However, the attackers withdrew soon as they did not prepare for a long siege. Ujiyasu Hojo, who was the lord of the clan, avoided fighting against Kenshin but waited patiently for the withdrawal. After Kenshin went back to his home, Ujiyasu got the territories and the retainers in the region back to the same side.

The portrait of Kenshin Uesugi, owned by the Uesugi Shrine (licensed under Public Domain via Wikimedia Commons)

The second crisis occurred in October 1569 (according to the luna calendar). Shingen Takeda from Kai Province, which is currently Yamanashi Prefecture, invaded the Hojo’s territories and reached Odawara Castle on the 1st of October. Shingen first attacked the main gate, called Hasuike-mon (which means lotus-pond gate), and set the castle town on fire. Shingen’s troops also torched the hall of Ujimasa Hojo, Ujiyasu’s successor. Shingen stayed at Odawara for only five days and returned to his home. However, these two crises had a big impact on the Hojo Clan, especially on Ujimasa. When he followed his father’s position, he started to fortify Odawara Castle more and more. He probably thought that if he could build a castle that could withstand a long siege, no enemies would ever destroy it.

The portrait of Shingen Takeda, owned by Jimyo-in, in the 16th century (licensed under Public Domain via Wikimedia Commons)

The portrait of Ujimasa Hojo, owned by Odawara Castle (licensed under Public Domain via Wikimedia Commons)

Goyomai Enclosure, where Ujimasa’s hall was built

Completion of the Castle by Ujimasa and Ujinao Hojo

The Hojo Clan reached its peak in the period of Ujimasa and his successor, Ujinao. This was because Kenshin died in 1578 and the power of the Takeda Clan decreased. The Hojo ruled most of the Kanto Region and built the network of their branch castles to maintain their government. Odawara Castle became the center of it. Ujimasa also fortified the castle. For example, the third enclosure was built on a plain land around the second enclosure. After that, the outer third enclosure was also built on a hill behind the main portion of the castle. They were constructed to protect the castle from potential enemies attacking it from the front and from the back. Furthermore, a large ditch was built to separate the highest hill around the castle, called Komine-Okane-no-dai, next to the outer third enclosure. All of them were made using soil. It was dug to create very steep moats and was mounded to make high earthen walls. The soil around the area came from volcanic ash, which is called Kanto loam layer. It’s naturally slimy, which made enemies slipped when they walk on the surface. The bottoms of the moats were also partitioned forming many square partitions, called Shoji-bori (which means sliding paper door-moat) and Une-bori (which means hilling-moat). If enemies fell to the bottom, they would be trapped and would never be able to escape from it.

The portrait of Ujinao Hojo, owned by Hounji Temple (licensed under Public Domain via Wikimedia Commons)

The large ditch at Komine-Okane-no-dai Hill

The Shoji-bori system in Yamanaka Castle

The development of the castle was related to the situation of the whole country and the diplomatic relations with other warlords. When Nobunaga Oda defeated the Takeda Clan in 1582, the Hojo was forced to be subordinate to Nobunaga. However, Nobunaga was killed during the Honnoji Incident in the same year. The Hojo, Tokugawa, Uesugi Clans battled each other in order to get the former territory of the Takeda Clan. A retainer of the Takeda Clan, the Sanada Clan gained power in order to be an independent lord by interrupting them. As time passed, Hideyoshi Toyotomi became the next ruler, ordering all the lords to stop fighting for themselves. Ujimasa ignored this new movement while other lords followed Hideyoshi by 1587. Ujimasa started a negotiation to serve the Hideyoshi side as well as the following year. One of the problems for the negotiation was about the Numata territory. There has been a dispute as to who was the true owner of the territory, between The Hojo Clan and Sanda Clan. Ujimasa asked Hideyoshi to resolve it. Hideyoshi’s decision was to give two thirds of the territory to the Hojo Clan and the other third to the Sanada Clan.

The portrait of Nobunaga Oda, attributed to Soshu Kano, owned by Chokoji Temple, in the late 16th century (licensed under Public Domain via Wikimedia Commons)

The portrait of Masayuki Sanada, privately owned (licensed under Public Domain, via Wikimedia Commons)

The Portrait of Ieyasu Tokugawa, attributed to Tanyu Kano, owned by Osaka Castle Museum (licensed under Public Domain via Wikimedia Commons)

The Portrait of Hideyoshi Toyotomi, attributed to Mitsunobu Kano, owned by Kodaiji Temple (licensed under Public Domain via Wikimedia Commons)

On the other hand, Ujimasa continued to fortify Odawara Castle in case the negotiations broke down. The highlight of it was to surround the entire area of Odawara including the castle, the town and the hills behind them. This was done by building moats and earthen walls, whose perimeter was about 9km long. This structure is generally called So-gamae (which means outermost enclosure). Ujimasa probably thought that enemies would never enter Odawara, because of this long perimeter, called So-gamae structure.

The red line shows the estimated line of So-gamae structure

The imaginary drawing of the So-gamae structure, from the signboard at the site

In October of 1589 (according to the luna calendar), an incident happened at the Numata territory. The Sanada Clan argued to Hideyoshi that the Hojo Clan forcibly got Nagurumi Castle on the Sanada’s side. This angered Hideyoshi and he finally decided to destroy the Hojo Clan completely. However, there are several questionable points about the incident. Some historians point out that It might have come from a deception of Hideyoshi and the Sanada Clan. Anyway, the battle between them may have been necessary. Hideyoshi wanted more territories to give to his retainers while Ujimasa didn’t want to surrender to Hideyoshi so easily. The So-gamae structure was eventually completed after the two-year constructions before the battle would happen.

Battle of Odawara

In March of 1590 (according to the luna calendar), about 220,000 of soldiers, led by Hideyoshi Toyotomi, rushed into the Hojo’s territories. The number of the Hojo’s defenders was said to be about 80,000. About 50,000 of them were in Odawara Castle. The Hojo Clan probably expected that their enemies would be weakened by the network of the Hojo’s branch castles before they reached Odawara Castle. If they sieged the castle in poor conditions, the Hojo Clan could make peace with them in better conditions. However, most of the Hojo’s soldiers were drafted farmers, nor were they experienced, nor were they trained, and nor were they motivated. The battles occurred on the 28th of March at Matsuida Castle in Kozuke Province (which is currently Gunma Prefecture), and on the 29th at Yamanaka and Nirayama Castles near Odawara. Surprisingly, Yamanaka Castle, which had strong defensive systems like Shoji-bori, was captured in less than one day by the overwhelmingly powerful military force of the Toyotomi side. After that, the castles’ network of the Hojo side eventually collapsed. As a result, only 5 out of tens of the branch castles survived at the end of May. That was the first miscalculation for the Hojo Clan.

The network system of the Hojo’s castles, from the signboard at the site

The Toyotomi’s troops reached Odawara Castle as early as in the beginning of April, surrounding the castle with about 180,000 soldiers. Hideyoshi launched the construction of his new stronghold, which would be called Ishigakiyama Castle, within the month. However, even with huge troops, they were not able to enter the castle, because they were blocked by the So-gamae structure. The structure was 30m wide at max and over 10m deep, with its slope at over 50 degrees. On the other hand, the Hojo side also miscalculated the features of the Toyotomi’s troops. Many of them were professionals and were equipped with enough supply systems. That meant they could survive in their battlefield for a very long time. They reached a much higher level in the combat than those of the Uesugi and Takeda Clans earlier on. As a result, the attackers and the defenders faced each other across the So-gamae structure in April and May.

The war map of Odawara Castle, from the signboard at the site

On the 5th of June, Masamune Date, who was the greatest warlord of the Tohoku Region, arrived at Odawara to serve Hideyoshi. That made the Hojo Clan know that no supporters would help them. The negotiation between the Toyotomi and Hojo sides started behind the scenes. Ujimasa’s successor, Ujinao Hojo was in charge of it. In Japanese, there is a figurative expression called “Odawara Hyojo” which means an inconclusive long conference. People generally think the Hojo didn’t know what to do during the siege. The fact might have been different from it. As time passed, four of the five surviving branch castles were captured in June. Only Oshi Castle was bearing being sieged by the Toyotomi troops like Odawara Castle. Ishigakiyama Castle, which had great stone walls, was completed on the 26th of June as Hideyoshi’s stronghold. Its appearance may have threatened the defenders of Odawara Castle, just a few kilometers away from it.

The portrait of Masamune Date owned by Sendai City Museum (licensed under Public Domain via Wikimedia Commons)

Ujinao finally surrendered to Hideyoshi on the 5th of July. It was said that the negotiation may have included a few territories reserved for the Hojo Clan. However, the decision of Hideyoshi, who completed his unification of Japan, was too strict to allow it. The four leaders of the Hojo side, including Ujimasa, were forced to do Harakiri. Even Ujinao, who made peace with Hideyoshi, was eventually expelled to Koyasan Temple. The Hojo Clan lost everything they had had. Some say that the decision had been planned from the beginning. The territorial allocation after the Battle of Odawara was as followed. Ieyasu Tokugawa moved from around the current Shizuoka Prefecture to the Kanto Region the Hojo Clan had had. Nobukatsu Oda, who was Nobunaga’s son but followed Hideyoshi, was also fired by Hideyoshi due to his rejection to move to Ieaysu’s previous territory. Hideyoshi gave the large vacant territories to his successor, Hidetsugu and his retainers. The satisfied retainers would monitor the actions of Ieyasu who was a potential enemy for Hideyoshi, killing two birds with one stone. In addition, the Sanada Clan got all of the Numata territory after the battle. Were they all coincidental?

The grave of Ujimasa Hojo, near Odawara Station

The Hojo Clan declined but Odawara Castle with the So-gamae structure was very effective against the attackers. For example, it was recorded that Kazuuji Nakamura, who owned Sunpu Castle, built So-gamae structure for his castle, too. In fact, Hideyoshi Toyotomi also built very long earthen walls to surround Kyoto, called O-doi, whose perimeter was about 23 km long. It was recently discovered that the walls had the Shoji-bori system. Hideyoshi also improved his home, Osaka Castle by building So-gamae structure from 1594. Some other lords, who joined the Battle of Odawara, built their own So-gamae as well, probably influenced by Odawara Castle.

The restored stone walls of Osaka Castle, used in its So-gamae structure

To be continued in “Odawara Castle Part2”