Also known as: 2009年9月9日, 9月9日, 9月9日はチルノの日
Works created to celebrate Cirno on September 9 (⑨ Day).
Often includes a reference to the date somewhere in the image or Commentary.
See also
- Kaguya Day (8th September)
- Koishi Day (14th May and 14th June)
- Nazrin Day (20th July)
- Satori Day (10th March)