Attempts at calendar reform have been prompted by two desires: to achieve a closer synchronization of the civil year of 365 days with the astronomic fact that the earth revolves around the sun in nearly 365¼ days, and to make a symmetrical division of the year. The Gregorian system now in use achieves a close synchronization of the civil year with the astronomic year, but the calendar lacks symmetry. A date of the month never coincides with the same day of the week in successive years, and the months have a varying number of days. Moreover, the year is not divisible into either two equal halves or four equal quarters.
One of the reforms suggested is to divide the civil year into 13 months, each of 28 days; this total of 364 days would be supplemented every six years (sometimes five), with the addition of an extra week to the last month.
A more popular suggested reform is the so-called World Calendar, which proposes dividing the year into four quarters of 91 days (three months of 30, 30, and 31 days), giving a total of 364 days. The extra day needed to make the calendar conform to the astronomic cycle is to be suspended between December 31 and January 1 of each year. It would be called either Blank Day or World Day, but would be dateless. In a leap year, there will either be two such days in succession, or another added at the end of June. Such a system would be almost entirely symmetrical. Each date of the month would always fall on a given day of the week, with a recurring one-year pattern. However, whereas the Gregorian reform affected neither the regularity of the days of the week, nor any possible rite occurring on them, the main disadvantage of the proposed World Calendar from the Jewish point of view is that it would destroy the fixity of the Sabbath. If in one year the Sabbath coincided with the day known as Saturday, in the following year it would shift to Friday.
Such a reform would be unacceptable to Judaism, whose day of rest depends on an unbroken sequence of six working days followed by the Sabbath (Ex. 20:9–10 and Deut. 5:13–14). Opposition has been expressed to any world authority rearranging the Sabbath, which is considered neither merely a social institution nor simply a day of prayer, but a fundamental of faith. In 1929, the Synagogue Council of America (comprising Orthodox, Conservative, and Reform congregations) declared that it would oppose any calendar reform likely to interfere with the regularity of the Sabbath. In 1931, J.H. *Hertz, British chief rabbi, vigorously opposed the World Calendar reform before a committee established by the League of Nations to consider the question.
B.D. Panth, Consider the Calendar (1944); J.H. Hertz, The Battle for the Sabbath at Geneva (1932); H. Watkins, Time Counts (The Story of the Calendar) (1954); S.B. Hoenig, in: Tradition, 7 (1964/65), 5–26.