The Dominical Letter Calendar is a version of the Gregorian Calendar that can be used either as a perennial calendar, or as a perpetual calendar of continuous weeks. Each day of the year is assigned a letter of the alphabet from A to G. 01-January is always A-day, and all the rest of the days of the year are lettered in sequence, each day of the year always having the same letter name. The letters continue through 31-December, which is also an A-day. The Sequence recommences with A-day on 01-January of the year following. 29-February (leap day), when it occurs, repeats C-day, the dominical letter day of 28-February.