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The Omagari Lock Gate
Photographed in 1951 by an American Military Doctor
Mar. 4th, 2018
Translated by Stefan Ramos
In the above photo are two hirata boats and a motor boat passing through the Omagari lock gate (which used to be called the Jogawa River southern lock gate) in the Kitakami canal. They are continuing on towards the direction of the Narusegawa River (in the background of the photo). In the bottom photo is a family helping with the lock gate guard’s work of opening and closing the gate. The one-story building on the right is the guard’s official residence.
Along the Kitakami canal, which extends 13.9 kilometers and connects the Narusegawa and Kyukitakami Rivers, there are differences in water levels. The water level on the canal side is lower, so ship navigation becomes dangerous during high tide. The lock gate was installed with the objective of regulating these water levels.
In 1907 (Meiji 40), a wooden lock gate was established at the converging waterways of Kama and Omagari on either side of the Jogawa River with the objective of preventing sediment influx and counter-currents during floods. Because of the destruction from the high tide in 1913 (Taisho 2), a second concrete lock gate was built and construction finished in 1916 (Taisho 5).
The double doors of the lock gate are made of wood. The gates were opened and closed by turning a man-powered device called a kagurasan (capstan). The origin of the word kagurasan is unknown, but the framework is set up with squared timber. There is a thick log in the middle that acts as an axis; into the axis are inserted two wooden poles that when pushed by people would wind up the rope connected to the top part of the doors. This would open and close the doors. There was one kagurasan attached to each door, so this work would happen on the other river bank as well.
After the Meiji period small-sized steamboats went into commission on the canals. As a water route that connected the Shiogama and Ishinomaki ports, the Kyukitakamigawa River basin transported people and goods. Even after the war into the 30’s (1955-1964) of the Showa period, one could see the tranquil scene of motorboats pulling hirata boats carrying building materials like wood, river sand, and well stones.
The doors of the Omagari lock gate were switched with steel doors in 1966 (Showa 41), and many remember the mechanization of the opening and closing equipment. It is unknown for how long the prefecture stationed a guard there, but the gate deteriorated, lost the ability to open and close, and was removed. Now sometimes boats coming and going choose to sail at high tide. (Local Historian, Seiji Henmi)
<Please let us know if you have any information>
You can browse the published photos on the photographer’s eldest son, Alan Butler’s, website “Miyagi 1951”. https://www.miyagi1951.com/
Please feel free to contribute any information regarding these photos to Mr. Henmi at 090(4317)7706.
米軍医が撮った1951、石巻地方＜８＞ 大曲閘門
上の写真は、北上運河の大曲閘門（こうもん）（旧名は定川南閘門）を通過する発動機船と、ひらた船２隻。鳴瀬川の方向（写真奥）に向かって進んでいます。下の写真は、閘門看守人の開閉作業を手伝う家族。右手にある木造平屋の建物は官舎です。
旧北上川と鳴瀬川を結ぶ北上運河（延長１３．９キロ）の間には、水位差があって運河側の水位が低く、満潮時は船舶航行が危険になります。このために水位調節を目的に設置するのが閘門です。
県は１９０７（明治４０）年、定川を挟んで運河が合流する釜と大曲に、土砂流入・洪水逆流防止の目的で、木造閘門を新設しました。１３（大正２）年の高潮被害で損壊したためコンクリート積み閘門（２代目）を新築し、１６（大正５）年７月に完工します。
閘門の門扉は、木製で観音開きです。「神楽桟・かぐらさん」（ろくろ又は巻き車）と呼ばれた道具を人力で回転させて開閉します。
神楽桟の語源は不詳ですが、角材で枠を組み、中央に回転軸となる太い丸太を立て、軸に差し込んだ２本の木の棒を人力で回すことで門扉上部に連結したロープを巻き取り、開閉します。門扉１枚に１台の神楽桟が付属し、対岸でも作業中です。
運河には明治以降、小型蒸気船が就航。北上川流域と石巻港・塩釜港を結ぶ水上交通路として人と物を運びました。戦後も昭和３０年代まで木材、川砂や井内石の建築資材を積むひらた船を発動機船が引く、のどかな光景が見られました。
大曲閘門の門扉は１９６６（昭和４１）年、鋼製門扉と交換、開閉装置が機械化されたと思われます。県が看守人をいつごろまで配置したか不詳ですが、現在は老朽化から開閉機能を失って門扉が撤去され、たまに往来する船は満潮時を見計らい航行しています。（郷土史家・辺見清二）