Undoukai is the Japanese word for a sports day or athletic meet, a long-running school and community tradition in Japan centred on races, relays and team events. Music in this bright march style is commonly associated with those outdoor festivals, where it builds excitement for children and spectators. Short clips like this circulate online as a generic sports day cue, reused in edits, anime references and playful competition videos whenever a creator wants an instantly cheerful, school festival atmosphere without a full soundtrack.