A perennial calendar is the same every year—unlike the annual Gregorian calendar, which is revised each year as calendar dates shift to different weekdays.

A perennial calendar requires the number of weekdays in the year to be evenly divisible by the number of days in the week. This can be achieved by shortening the calendar year to 364 weekdays. To accomplish this, some favor designating one day each year, and another in leap year, as a "blank day." A blank day is a calendar date removed from the seven-day cycle of the week. These are often proposed as world holidays. But blank days are objectionable to sabbatarians, or to religious groups who regard every seventh day (sabbath) as a holy day. They feel obligated to include every day in the sabbatical sequence of weekdays, so there are never more than six days between sabbaths.

The Long-Sabbath Calendar Plan achieves a perennial calendar without the use of blank days. It does so by extending some sabbath days (Saturdays and Sundays) for 36 hours.

January 1, (Gregorian) will fall on a Sunday; 364 days later, December 30, falls on a Saturday. The Long-Sabbath plan extends that Saturday at the end of the year, a Jewish sabbath, for 36 hours. It likewise extends for 36 hours the following Sunday, which most Christians recognize as a sabbath.

So Saturday, December 30, , will be followed immediately by Sunday, January 1, . Seventy-two hours are covered by only two weekdays, rather than the ususal three. By following this procedure every subsequent year, the date of December 31 will be elimated from the calendar.

In this way the Long-Sabbath plan achieves a perennial calendar without interrupting the continuity of the sabbatical cycle.

Where does it say in the scriptures that a day is 24 hours, and fixed by the solar cycle? Not in the first verses of Genesis. In that passage, which is the scriptural basis for the sabbatarian obligation to worship on the seventh day, two full days (evening and morning) are said to have elapsed even before creation of the sun and the moon!

The next leap year after will occur in . When January 1 falls perennially on Sunday, the last Saturday in February will be the 25th. February's extra day in leap year can therefore be accommodated by extending the sabbaths of February 25th and 26th for 36 hours each. Following this plan in perpetuity, the irregular date of February 29th can be cancelled.

The Long Sabbaths at the end of the year will be known as "New-Year Sabbaths." Those near the end of February in leap year will be known as "Leap-Year Sabbaths."

Time can be recorded in two different ways for these 36-hour sabbaths. On the extended clock, time will proceed beyond 23:59 through 35:59. On the 12-hour clock, the long sabbaths will be divided into three 12-hour periods to be designated as follows:

• Saturday, December 30 always consists of:
  1. 12:00 a.m. through 11:59 a.m. (ante meridian)
  2. 12:00 p.m. through 11:59 p.m. (post meridian)
  3. 12:00 a.a. through 11:59 a.a. (ante annum)
• Sunday, January 1 always consists of:
  1. 12:00 p.a. through 11:59 p.a. (post annum)
  2. 12:00 a.m. through 11:59 a.m.
  3. 12:00 p.m. through 11:59 p.m.

• Saturday, February 25 in leap year consists of:
  1. 12:00 a.m. through 11:59 a.m.
  2. 12:00 p.m. through 11:59 p.m.
  3. 12:00 a.q. through 11:59 a.q. (ante quadrennium)
• Sunday, February 26 in leap year consists of:
  1. 12:00 p.q. through 11:59 p.q. (post quadrennium)
  2. 12:00 a.m. through 11:59 a.m.
  3. 12:00 p.m. through 11:59 p.m.

The New Year will always begin in the middle of a solar day, as the 36-hour calendar day of Saturday, December 30 leads into the next 36-hour calendar day of Sunday, January 1. (The "calendar day" and the "solar day" are not always the same in the Long-Sabbath Calendar. They are also not the same when daylight-savings time shortens one day each year by one hour, and lengthens another day each year by one hour.)

The year will always contain exactly 52 weeks of seven calendar days, and can be divided evenly into 26-week halves and 13-week quarters.

To distinguish the style of dating introduced in , those dates according to the Long-Sabbath Calendar can be designated by the abbreviation, "L.S." Dates according to the present calendar the Long-Sabbath Plan replaces can be designated by the abbreviation, "N.S." or "New Style," which was once used to distinguish our present calendar's dates from the "Old Style," Julian calendar.

Why ? One lesson of Y2K, the calendrical software correction required as we moved from year numbers beginning with "19" to "20," was that preparations for calendar-change must be made well in advance. It is now foolish to propose that even a minor reform of the calendar take place sometime in the next five or six years. With the proposed change instituted decades in advance, calendar programming can be altered well ahead of the target date, and public panic can be avoided.