· The Fast of Esther is not one of the four public fasts ordained by the Prophets. Consequently, we are more lenient in its observance; pregnant women, nursing mothers, and those who are weak are not required to observe it.
· The Anenu prayer in the Amidah prayer, Selichot, and the special Torah reading for fast days are required on the Fast of Esther.
· If the thirteenth of Adar falls on Shabbat, the fast is observed on the preceding Thursday, the eleventh of Adar. Because if Purim falls on the fourteenth, we do not put off the fast for the following day; as is the case for example, when the Ninth of Av falls on Shabbat; nor do we observe it on Friday out of deference to Shabbat. The only public fast that can fall on a Friday is the Tenth of Tevet.
· Tachanun is not said at Minchah on the Fast of Esther. Some people observe the custom of wearing their Shabbat clothing at Mincha on the Fast of Esther, since the Megillah reading follows immediately afterwards unless Purim falls on Sunday, in which case the fast is on Thursday but the Megillah is not read until Saturday night.