大蔵は古くから交通の要所でしたが江戸時代に西国街道が整備され大蔵谷宿として栄えました。東西を貫く街道と平行に脇道が、またそれらを南北につなぐ多くの路地が張り巡っています。
大蔵がの西端は建物がせり出して見通しが悪く、その先は街道がL字状に曲がります。これは「遠見遮断」といい敵の進軍を阻害するため宿場や城下の入口に設けられた仕掛けで特にL字状の通りは「鍵の手」と呼ばれています。また敷地が道に対してノコギリの歯状になっているのは建物の陰に隠れて敵を攻撃する工夫でこれも遠見遮断といえます。
Okura was an old important transportation hub and after the Saigoku Highway was improved in Edo period it flourished as Okuradani stage. The Highway and its sideroads pass from east to west and many alleys from south to north cross them.
The Saigoku Highway reaches the building at the west end of Okura and turns right and just left. That is called Tomi Shadan (visibility shutdown) as a trick to prevent the enemy from advance and set at the entrance of the town serving as a stage or the castle town. The L-shaped road is specially called kagi-no-te (shape of key). The limb of the Highway in the town zigzagged widely, so they could attack enemies from the place behind the buildings. This was a kind of Tomi Shadan.
明石ヘリテージマップ『大蔵』2014
現況 現在も西国街道沿いに残存しています。