Miku Day is an annual celebration of the virtual idol Hatsune Miku, held every March 9th. The date's significance comes from a Japanese wordplay known as goroawase, where the number '3' can be pronounced as 'Mi' and '9' as 'Ku,' combining to form 'Miku.' Fans across the globe participate by sharing fan art, music, and memes to honor the teal-haired diva. While it started as a grassroots movement among the Vocaloid community on platforms like Nico Nico Douga and Pixiv, it has evolved into a global phenomenon with major participation from Sega and official brand collaborations. In meme culture, Miku Day is a time for the community to flood social media with tributes, often incorporating her signature leek (negi) and the number 39, which also translates to 'Thank You' in Japanese.