The koto is a traditional Japanese stringed instrument, and this cute, short version of its sound became a staple punctuation mark in online video editing. Instead of using a full track, creators drop in the brief riff to flag a Japan-inspired or anime-inspired moment in seconds. It spread through soundboards, meme edits and streams alongside other anime staples like Tuturu, where a single recognisable clip does the work of explaining the joke. Its brevity and clear cultural shorthand keep it useful for transitions, reveals and reaction beats.