An interesting fact

Today I learned that at the beginning of battles between samurai in Japan, it was customary to shoot arrows with a special head that made them whistle during the flight.

The aim of the whistle was to declare the beginning of the battle (since the honor of the samurai does not allow him to attack by surprise), and to mobilize the local spirits for your side.

The Mongols used similar arrows during hunting; the whistle would distract the animal, and while it was confused it was easy to hit it with a regular arrow.

Source: https://en.wikipedia.org/wiki/Kabura-ya_(Japanese_signal_arrow)