Kabura-ya

Kabura-ya, meaning turnip-headed arrow, is a specialized category of Japanese arrow used by feudal samurai, fitted with a carved or perforated bulb of deer horn or wood that produced a whistling sound in flight. During the Heian period these arrows were shot before formal battles as a ritual signal, believed to ward off evil influences and summon protective kami, and elaborate exchanges of them could precede close combat by dozens or even a hundred shots on each side, as recorded at the 1183 Battle of Kurikara. Warriors also tied messages to kabura-ya and shot them into enemy fortresses or camps. The practice faded after the Heian period as warfare grew more pragmatic. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/