Older sister day.
First established in 1991 by cartoonist Hatada Kunio (畑田国男) according to a legend about Saint Nicolaus and the three sisters.
There's also "Younger brother day" on March 6th, "Older brother day" on June 6th, and "Younger sister day" on September 6th.December 6thStiff in various ways, aren't you, Onee-sama?Hair band....Very much so, in many ways, yes.
