Zairja

thumb|300px A zairja (; also transcribed as zairjah, zairajah, zairdja, zairadja, and zayirga) was a device used by medieval Arab astrologers to generate ideas by mechanical means. The name may derive from a mixture of the Persian words zāycha ( "horoscope; astronomical table") and dāyra ( "circle").

Ibn Khaldun described zairja as: "a branch of the science of letter magic, practiced among the authorities on letter magic, is the technique of finding out answers from questions by means of connections existing between the letters of the expressions used in the question. They imagine that these connections can form the basis for knowing the future happenings they want to know." He suggests that rather than being supernatural it works "from an agreement in the wording of question and answer ... with the help of the technique called 'breaking down (i.e. algebra). By combining number values associated with the letters and categories, new paths of insight and thought were created.