noun
intentionally curved road section; defensive bend in a road
Refers to a deliberate curve or zigzag in a road, historically designed to slow attackers or impede visibility. Often used in descriptions of castle approaches or old town layouts.
城下町には、敵の侵入を防ぐために鍵の手が設けられていた。
In the castle town, intentionally curved road sections were built to prevent enemy intrusion.
この道は鍵の手になっていて、先が見通せない。
This road bends sharply, so you can't see what's ahead.