February 22nd, the Ninja Day

Recently, the day of February 22 was declared the "National Ninja Day", at the initiative of 5 Japanese prefectures renowned for their ninja-related history: Kanagawa, Nagano, Mie, Shiga and Saga.

If you wonder, there wasn't any ninja historical event on February 22nd... The day was actually selected due to a word play in Japanese: because it is written as 2/22, and the number 2 is pronounced in Japanese "ni", the first syllable of the word ninja...