Black Friday (shopping) the holiday season, beginning on the day after Thanksgiving. When this was recorded in the financial records, once-common accounting practices would use red ink to show negative amounts and black ink to show positive amounts. Black Friday, under this theory, is the beginning of the period when retailers would no longer be "in the red", instead taking in the year's profits. The earliest known published reference to this explanation occurs in "The Philadelphia Inquirer" for November 28, 1981. In 2013, an internet rumor alleged that the phrase originated in the American south before the Civil War, from the practice of
Leap year starting on Friday share this characteristic. Leap years that begin on Friday, along with those that start on Sunday, occur most frequently: 15 out of the 97 (≈ 15.5%) total leap years in a 400-year cycle of the Gregorian calendar. Thus, the overall occurrence is thus 3.75% (15 out of 400). Like all leap year types, the one starting with 1 January on a Friday occurs exactly once in a 28-year cycle in the Julian calendar, i.e. in 3.57% of years. As the Julian calendar repeats after 28 years that means it will also repeat after 700 years, i.e. 25 cycles. The year's