Ushigome-mon Gate was located between the Ushigome-bori and Iida-bori Moats. A weir was constructed under Ushigome Gate in order to protect the earthen bridge that dammed the water in Ushigome-bori Moat and control the water level. When JR Iidabashi Station’s platform was relocated in 2017, remnants of stone paving believed to comprise a portion of the weir was discovered for the first time anywhere in the outer moat area. Photographs from the Meiji period contain images of the weir’s outfall and the sections of stone paving uncovered at the site are thought to have comprised a portion of the aqueduct located immediately in front of the outfall. Currently, the section of stone paving discovered is 2017 is preserved in its original location directly under the train platform. A portion of the platform’s surface has been modified in order to express the scope of the area that was covered by the stone paving. In addition, a portion of the paving removed from the site is on display in the plaza in front of the Station. It enables visitors to get a sense of the weir’s size. Unfortunately, no documents or records that describe the weir’s structure have been discovered. A similar type of structure known as the Sekiguchi Weir, however, which was constructed during the same period and transported water into the city from the Kanda River, provides us with some insights about weir technology and design. Located in present-day Bunkyo Ward’s Sekiguchi district, the arrangement of stone material used to construct the Sekiguchi Weir’s channel resembles that of the stone paving discovered along the outer moat in 2017. Also from the platform you can see the current waterway connecting the moats.
牛込門・牛込駅周辺の変遷 The Transition of Usigome-mon Gate and Ushigome Station Areas 外堀は、1660(万治3)年、牛込・和泉橋間の堀さらいが行われ、外堀(神田川)をさかのぼって、牛込橋までの通船が可能となり、神田川沿いに河岸ができました。牛込橋東側の堀端には、揚場町の「町方揚場」と御三家のひとつである「尾張様物揚場」があり、山の手の武家地や町人地へ薪や炭などの荷物を運ぶ軽子が、「軽子坂」を往来したといわれています。 牛込門から城内に入ると武家屋敷が連なり、他方、堀端から現在の神楽坂の辺りは、善国寺(毘沙門天)の坂下の地域が武家地、早稲田側には寺町が形成されました。寺の門前には町屋が建ち並び、江戸名所の一つとして賑わいを見せていました。 明治になると、城外の新宿区側には、空き家と化した武家屋敷跡が芸妓置屋や料亭となり、神楽坂花街が形成されていきました。他方、城内の千代田区側の武家屋敷跡に学校などが建てられました。 牛込土橋東側の堀は、1984(昭和59)年、再開発事業により暗渠となり、現在に至っています。また、鉄道整備においても削られずに残された牛込門周辺の土塁は、1911(明治44)年、牛込・喰違間の土手遊歩道を外堀保存のため公園とする計画が決定され、1927(昭和2)年、「東京市立土手公園」として開設されました。現在でも国史跡指定区域に、外濠公園として歴史的風致が保全されています。
In 1660, the section of the outer moat located between Ushigome-bashi and Izumi Bridges was dredged. This made it possible for boats to travel up the outer moat (Kanda River) to Ushigome-bashi Bridge. In addition, banks were constructed on both sides of the Kanda River. The bankside area on the eastern side of Ushigome-mon Bridge was home to the Agebachō neighborhood’s “community landing,” and “the Owari House Landing,” which was controlled by the Owari, one of the three branches of the Tokugawa clan. Both sites were used to offload arriving cargo. Porters transporting firewood and charcoal to warrior estates and commoner neighborhoods in the Edo’s Yamanote area are said to have traveled from these moat-side landings up an incline known as Hill of Karuko. Entering the castle grounds from Ushigome-mon Gate, warrior estates lined the street. The area located at the foot of Zenkoku Temple between the moat banks and present-day Kagurazaka was home to warrior estates and, on the Waseda side, there were Buddhist temples. Commoner residences lined the space in front of the temple gates and the area emerged as one of Edo’s most bustling sites. Entering the Meiji period, unoccupied former warrior estates outside the castle walls on the Shinjuku Ward side came to host restaurants and establishments employing geisha entertainers and courtesans. This led to the establishment of the Kagurazaka pleasure quarter. In contrast, schools and other institutions were constructed on the grounds of abandoned warrior estates inside the castle wall on the Chiyoda Ward side. In 1984, the moat on the eastern side of Ushigome-bashi Bridge was enclosed in conjunction with a local reedevelopment project. It remains covered today. In addition, in 1911, the government presented a plan to transform the portions of the moat embankment in the vicinity of Ushigome-mon Gate that survived the construction of the railroads into a public park and preserve remaining portions of the outer moat between Ushigome and Kuichigai as a pedestrian walkway. This resulted in the creation of Tokyo Dote City Park, which was founded in 1927. Even today, historic landscapes located inside the area officially designated as a national heritage site have been preserved in the form of Sotobori Park.
The section of the outer moat located between Ushigome to Ichigaya was constructed by utilizing the topography of the Kanda River valley. In addition, because the Yotsuya and Kojimachi sections of the moat were located on a ridgeline, which cut across the Kanda Plateau, moat construction in those areas required the execution of a large-scale infrastructure project in which sections of the Plateau were removed and the moat was extended to the valley in the vicinity of the reservoir on the Akasaka side. Groups of domainal lords were mobilized to carry out the project and each group was required to remove a predetermined amount of earth from the plateau. The outer moat reached its highest point in the vicinity of Kuichigai Gate. From there, the water level gradually lowered as it passed through the channels linking Sanada-bori Moat with the Kanda River. In order to control the flow of water and prevent flooding, weirs were constructed to around gates, such as Ushigome-mon Gate, which were located on earthen bridges. These weirs were then utilized to control the water level in the moat. Furthermore, utilizing the natural topography, large earthen fortifications were constructed by building up sections of the Kanda Plateau on the present-day Chiyoda Ward side of the moat in order to improve the Castle’s defenses. That project resulted in the establishment of a steep embankment. Edo Castle’s outer moat boasts a total length of approximately 14 kilometers. The approximately 4-kilometer, 38-hectare section between Ushigome and Akasaka Gates is a designated as a National Historic Site. Visitors to the site can see the ingeniously constructed outer moat filled with water, the stone walls of the Castle’s outer gates, and the shape of its earthen fortifications.
江戸城外堀 The History of Edo Castle Outer Moat 江戸城は、本丸・二の丸・三の丸・西の丸・北の丸・吹上からなる内郭を内堀が囲み、その表門が大手門でした。外堀は、雉子橋門から時計回りに、一橋門、神田橋門、常盤橋門など諸門をめぐり、呉服橋門から虎ノ門、溜池から四谷門、市谷門、牛込門を経て、現在の神田川に入り、小石川門から浅草門で、隅田川に至る堀でした。外堀工事は、1606(慶長11)年に雉子橋から溜池までの堀を構築後、1618(元和4)年に駿河台が掘削されて平川(現日本橋川)の流路に付け替えられ、神田川が誕生しました。この工事で、平川は堀留橋で締め切られ、独立した堀となりました。 1636(寛永13)年には、天下普請で外堀が構築され、江戸の総構が完成します。この工事は、雉子橋から虎ノ門に至る外堀の総石垣化と枡形築造を前田・細川・池田・黒田家など西国外様大名(石垣方六組)、牛込土橋から赤坂土橋にかけての外堀掘削と土塁の構築を東国大名(堀方七組)が行いました。 その後も幕府は、外堀を維持するために大名の手伝普請による堀さらいをしました。牛込~市谷間の堀は、市谷~四谷間より水位が下がり、土砂が堆積し、蓮が繁ったため、普請奉行の管理下で頻繁にさらいが行われました。また、町人にも堀にゴミを捨てないよう町触も出され、外堀の維持・管理が行われました。
Edo Castle’s inner hull was comprised of six citadels: the main, second, third, western, northern, and fukiage citadels. The entire inner hull was encircled by an internal moat and Ōte-mon Gate served as its main entrance. The Castle’s outer moat originated at Kijibashi-mon Gate and passed, in clockwise direction, through Hitotsubashi-mon, Kandabashi-mon, Tokiwa-bashi-mon, Gofukubashi-mon, and Torano-mon Gates. It then extended from Castle reservoir through Yotsuya-mon, Ichigaya-mon, and Ushigome-mon Gates before ultimately flowing into the present-day Kanda River. From there. it served as a canal, which passed through Koishikawa-mon and Asakusa-mon Gates and ultimately converged with the Sumida River. The outer moat’s development began in 1606 with the construction of a canal from Kiji-bashi Bridge to the Castle reservoir. The second stage in its evolution came in 1618, when portions of the Kanda Plateau were removed and the canal was redirected towards the Hira River. That process gave birth to the Kanda River and transformed the Hira River, which was closed off at Horidome-bashi Bridge, into an independent canal. The outer moat was finally completed in 1636, when feudal lords from eastern and western Japan were mobilized to construct its remaining portions. Specifically, western domainal lords, including the Maeda, Hosokawa, Ikeda, and Kuroda Houses, were ordered to supervise the construction of stone walls and the square masugata enclosures used to protect the castle gates along the section of outer moat between Kiji-bashi Bridge and Torano-mon Gate. In constrast, domainal lords from eastern Japan were order to dig a canal between Ushigome-bashi and Akasaka-bashi Bridges and construct earthen fortifications. In order to maintain the outer moat, the Tokugawa shogunate mobilized domainal lords from around the country to dredge it. In particular, the section of the moat between Ushigome and Ichigaya required frequent dredging because the water level often receded, resulting in the accumulation of silt on the moat floor and the development of water lilies on its surface. Such dredging projects were carried out under the supervision of the shogunate’s Governor of Construction. In addition, the city authori-ties attempted to keep the outer moat free of debris by issuing official proclamations banning the residents of commoner neigh-borhoods from disposing of garbage in the moat.
赤坂門:長崎大学附属図書館蔵
Akasaka-mon Gate: “Photo Tokyo Past and Present” Hiroshi Nozawa
喰違:『絵本江戸土産』国立国会図書館蔵
Kuichigai-mon Gate: “Edo Souvenir in Pictures” National Diet Library
そのほか:『旧江戸城写真帖』東京国立博物館蔵
Others: “Old Edo Castle Photo Collection” Tokyo National Museum
ID 489とID 11462は神田川の下流方向を撮っています。左から植物に覆われて突き出しているのは文京区の「市兵衛河岸」です。小屋があり、ガラス扉の中にイスが見えます。昭和55年の住宅地図では「都市◯地再開発(事)飯田橋工区」とあり、工事の詰め所のようなものでした。 その奥、首都高速道路の橋脚ごしに見えているのは「飯田橋公共職業安定所」(現・ハローワーク飯田橋)。さらに右にクレーンが見えているのは、中央大学の旧後楽園校舎(文学部)を解体しているのでしょう。 神田川の右岸は千代田区です。古めかしい「釣り具」の看板が見えるのは、かつて外堀や神田川で釣りを楽しむ人がいたことを示しています。 ID 490−491とID 11463−11464は、やや手前の橋を撮影しています。誤解されがちですが、この橋は文京区と千代田区をつなぐ「船河原橋」です。
ID 13055、13084-85は南側から北側の大曲までを撮影しています。目白通りは2車線ずつの対面通行で、神田川の上に首都高があり、その下で川を渡るのは白鳥橋です。目白通りを通るとT字型の「大曲交差点」となります。信号機は一見すると確認できませんが、カバーなどで覆われているだけでしょう。 白鳥橋の上、首都高が途切れたようになっていてるのは、後に飯田橋料金所を作る場所です。 首都高の下、向かって右側の歩道はおそらく利用ができず、バリケードやブロック、チェーンスタンド、コンクリートの土管らしきもの、大きな円環3つなどが並んでいます。作業小屋もあります。歩道の縁石をまたいで何台かの車が止まっています。おそらく工事のためでしょう。 左手前から奥に向けて、ヘルメット姿の作業員達は目白通りを大きく掘削しています。鉄骨や、穴を掘るための鉄板が並んでいます。 目白通りの地下には神田川の洪水対策として江戸川橋分水路があります。しかし東京都の資料によれば建設年は昭和47ー52年で、写真と時期があいません。また平面図で見ると、分水路が作られたのは神田川寄りで、写真とは反対側です。 文京区関口一丁目南部会は「昭和44年頃より江戸川橋ー下水管一本埋設」としています。現在の都の下水道台帳を調べると、江戸川橋分水路に沿って「早稲田幹線」があるのが分かります。工事は、この下水管に関係したものでしょう。
下水道台帳 大曲付近
少し前の昭和44年9月のID 12776-79では、大曲付近の掘削はまだ着手していないように見えます。まず下水管を整備し、そのあとで分水路の建設に着手したのでしょう。 ID 13085では、目白通りを「東京タワー」と書いたバスが北進中。また、トレードマーク「フクスケ」の広告塔は、福助株式会社でしょう。
ID 12215とほぼ同じ場所で、道を渡った高速の真下から道沿いの建物を撮影したものです。 建設中の坂道が、飯田橋料金所に上がる首都高のランプ。その手前の坂のように見えるのは目白通りの上り車線です。一番右にガードレールが見えます。 この区間は神田川の「江戸川橋分水路」建設のため通行止めになっています。一番、奥に工事車両が見えます。その先は新白鳥橋に分岐する交差点があります。 道路脇の建物は新小川町で、出光とロゴマーク()と看板「全軽和」、ナショナル(現、パナソニック)のロゴマーク()などが見えます。「全軽印」の看板のビルの左は東京電力新小川町変電所で、現在も変わりません。その左側の消火栓広告は「きもの英」です。