Kaginawa (鈎縄) is the combination of the words kagi meaning hook and nawa meaning rope.  The kaginawa is a type of grappling hook used as a tool in feudal Japan by the samurai class, their retainers, foot soldiers and reportedly by ninja. Kaginawa have several configurations, from one to four hooks. The kagi would be attached to a nawa of varying length; this was then used to scale a rather large wall, to secure a boat, or for hanging up armor and other equipment during the night. Kaginawa were regularly used during various sieges of miscellaneous castles. The nawa was attached to a ring on one end which could be used to hang it from a saddle.
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Kaginawa: It's History & Use (Kokusai Hojojutsu Kenkyukai)