Works created to celebrate [[Cirno]] on September 9 ([[circled 9|⑨]] Day). 
Often includes a reference to the date somewhere in the image or [[commentary]].

h4. See also

* [[Kaguya Day]] (8th September)
* [[Koishi Day]] (14th May and 14th June)
* [[Nazrin Day]] (20th July)
* [[Satori Day]] (10th March)

* [[Tag group:Holidays and Celebrations]]
2009年9月9日 9月9日 9月9日はチルノの日