February 10th is a date pun for Kawashiro Nitori from Touhou. Since February 10th can be read as "2 (ni) 10 (to)" it's a day when artists draw and post artworks with Nitori. For those who missed February 10th, there is also a tag called "February 11th is the day for those who missed Nitori Day." Nitori day is also celebrated on the 20th of every month.

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