rast RAST MUSICOLOGY JOURNAL | WINTER 2023, 11(4) 589-602 Research Article 589 Abstract The use of microtones in guitar music is not an innovative phenomenon as it is thought. It has been used for different tuning systems and by composers working on non-12edo music throughout history. Although this concept is not as widespread as conventional guitar music, many experimental studies have been conducted to tune microtones more accurately. This article aims to present practical tools for the reader on methods to produce microtones on the guitar, especially Tolgahan Çoğulu’s adjustable microtonal guitar project, and the developments in microtonal guitar music in Türkiye since the project began in 2008 to 2021. The fndings on this topic are shared from a guitar music specialist’s perspective. It aims to be helpful, especially for guitarists who are unfamiliar with microtonal music approaches in guitar music. The study consists of two parts. In the frst part, the microtonal strategies in guitar music were compiled. Practical ways to achieve microtones on conventional guitars, non-12edo fxed fret layouts, fretlets concept, and movable fret guitars are examined individually, and their advantages and disadvantages are listed in terms of their usability. In the second part, the attainments of the Adjustable Microtonal Guitar Project were examined. By using the principles determined by Andres Segovia in the formation of modern guitar music in the 1920s as a model, the composers who composed for this instrument, the performers who used the instrument, the success in the presentation of the project in social media, the awards it won in international competitions, microtonal guitar competitions and festivals, academic and pedagogical studies were researched. The fndings show that the adjustable microtonal guitar gives precise results in tuning compared to the other strategies mentioned. Even though it causes diffculties in changing the frets between different pieces in terms of time, it is the most suitable result for using microtones on the guitar, as it makes it possible to perform all kinds of work. In the project’s short history, the Adjustable Microtonal Guitar project crossed national borders and created its ecosystem with the innovative efforts of the inventor. Keywords Adjustable microtonal guitar, instrument development, microtonality on guitar music, Tolgahan Çoğulu Introduction Even though two decades have passed since the millennium, the idea of microtonality in guitar music is still perceived as odd by many classical guitarists. However, it does not need to be. Contrary to popular belief, the classical guitar is not very old, and many important milestones have been passed in just the last hundred years. Earlier traditions in tuning systems and musical aesthetics were abandoned gradually, parallel to Western art music developments as the 20th century approached. In the frst half of the twentieth century, the guitar was separated from the shadow of famenco and redefned as a Western art music instrument, thanks to Andrés Segovia’s groundbreaking efforts. Advances in its acoustic structure also enabled the guitar to be heard by the masses in concert halls. Non-guitarist composers fnally started considering composing for this instrument, with its more comprehensive timbral range. Moreover, a vast number of arrangements from other instruments’ repertoires have been made by guitarists. As the guitar’s reputation spread worldwide, the gap between Western art music movements and classical guitar music has shrunk drastically. New compositions brought new techniques; guitar music is no longer defned by the 19th century’s limited approach to harmony and form. After the 1950s, a new generation of guitarist composers started to appear in the guitar feld. Leo Brouwer, Nikita Koshkin, Roland The microtonal guitar: Türkiye’s Segovia moment Emre Ünlenen Assoc. Prof. Dr., State Conservatory, Music Department, Anadolu University, Eskisehir, Turkiye. Email: emreunlenen@anadolu.edu.tr Phone: +90 5467342096 ORCID: 0000-0002-9680-2248 DOI 10.12975/rastmd.20231146 Submitted September 13, 2023 Accepted December 28, 2023