According to the Shi'a faith, sawm (plural siyam), fasting, is a pillar of the Islamic code. There are four kinds of siyam: wajib (compulsory), mustahab (recommended), haram (forbidden) or makruh (undesirable). The fasts made incumbent by the shari'ah (code of religion) are those of the holy month of Ramadhan. Other fasts become incumbent for some specific reason, for instance "sawm Kaffarah" (the penalty fast), "badal" (in lieu of sacrificing an animal), in lieu of someone else, "nadr" (as a vow, or oath). The fasts of the months of Rajab and Sha'ban are desirable as well as other fasts too numerous to mention in this brief work. Fasting on the two 'id days and "ayyam at-tashiq" (the three days after hajj) is forbidden; to fast on the days of 'Ashurah and 'Arafat are undesirable (according to many the 'Ashurah day fast is strictly forbidden).
Details concerning the conditions and actual performance of a certain fast, as well as the courtesies (adab) and recitations associated with each, may be found in the large number of books on this topic. The Shi'as are extremely particular about the Ramadhan fasts: many of them would rather die of thirst or hunger than not undertake it.
