Castle Defenses: Ishi Otoshi 城の防御：石落

Official explanation

These openings in the floor, called ishi otoshi, allowed defenders to repel enemies who reached the castle’s stone-wall foundation below. To prevent people and objects from falling through the openings, the ishi otoshi were covered with wooden boards that could be removed when the castle came under attack.

Ishi otoshi were typically built at corners to address blind spots in a castle’s defenses, but Matsumoto Castle has additional openings at the midpoints between corners. It was thought that a determined attacker could climb the castle’s stone-wall foundation, which has a relatively gentle slope of about 57°. Putting ishi otoshi at the midpoints made it possible to prevent this and defend the castle against attackers who breached its outer defenses.

Read the full explanation

Although the name ishi otoshi (literally, “stone drops”) implies that they were used to drop stones, the openings are quite narrow. If Matsumoto Castle had ever come under attack, defenders would more likely have fired down at attackers with bows and muskets.

出典: 地域観光資源の多言語解説文データベース（観光庁） — www.mlit.go.jp/tagengo-db. この英語解説文は観光庁の地域観光資源の多言語解説整備支援事業で作成しました。
Source: Japan Tourism Agency, Multilingual Explanation Database. This English text was produced by the Japan Tourism Agency's multilingual explanation project and is shown unedited. Opening hours and services may have changed since it was written.