Ḥiyal

Ḥiyal (حيل, singular ḥīla حيلة "contortion, contrivance; device, subterfuge") is a term for "legalistic trickery" in Islamic jurisprudence. The main purpose of ḥiyal is to avoid straightforward observance of Islamic law in difficult situations while still obeying the letter of the law. An example of hiyal is the practice of "dual purchase" (baiʿatān fī baiʿa) to avoid the prohibition of usury by making two contracts of purchase and re-purchase (at a higher price), similar to the modern futures contract. A special sub-field of ḥiyal is "oath-trickery" (maʿārīḍ) dedicated to the formulation of ambiguous statements designed to be interpreted as an oath or promise while leaving open loopholes to avoid perjury. Views on its admissibility in Islam have varied by schools of Islamic jurisprudence (Madhhab), by time period, and by type of ḥiyal. A substantial literature on such tricks has developed in the Hanafi school of jurisprudence in particular.

The earliest development of this field is the Kitāb al-maḫārij fī l-ḥiyal ("book of evasion and trickery") by Muhammad al-Shaybani (d. 805). A more comprehensive treatment is the Kitāb al-ḥiyal wa-l-maḫārij by Al-Ḫaṣṣāf (d. 870). The study of ḥiyal was not uncontroversial in Islamic jurisprudence. It was at first classed as haram by the Shafiite school, although its great popularity eventually led to aspects of ḥiyal being recognized even in Shafiite treatises. By the 10th century, Shafiite authors wrote a number of ḥiyal treatises of their own, of which the work by al-Qazwini (died 1048) has survived, while others continued to denounce ḥiyal, among them al-Ghazali. Since the 15th century, Shafiite opposition to ḥiyal had mostly disappeared, due to the fatwas by Ibn Hajar al-Asqalani outlawing its criticism.

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