Kemalpashazade Ahmed Efendi (d. 940/1534), one of the most distinguished and prolific scholars and philosophers of the Ottoman era, presented systematic criticisms of some earlier foundational texts under the titles of "revision" (taghyir), "correction" (islah), and "refinement" (tajwid). His critical project incorporated a solid criticism of these seminal and influential works in linguistic, rational, and traditional sciences, both in form and in content. He also included Nasir al-Din al-Tusi's (d. 672/1274) Tajrid al-i'tiqad in this project. In his Tajwid, Kemalpashazade rewrote this work and wrote a commentary upon it, namely, Sharh Tajwid al-Tajrid. His interest in Tajrid was not limited to these two, for in addition to a separate commentary (Sharh al-Tajrid) he also wrote superglosses on some glosses of Tajrid, such as Hashiya li-Hashiyat al-Jalal. So far, neither his general project nor these two works have attracted sufficient scholarly interest. In this article, we focus on Kemalpashazade's studies on Tajrid and present a detailed study of Tajwid, as well as - and for the first time - its critical edition based on all of the extant manuscript copies. Thus, the article is in four parts: The Ottoman Tajrid Tradition: From Tajrid to Tajwid, Kemalpashazade's Studies on Tajrid, Kemalpashazade's Critique on Tajrid: Tajwid al-Tajrid," and Tajwid al-Tajrid.