《第四二胡協奏曲-愛恨情仇》是關迺忠在2008年，受新加坡華樂團音樂總監葉聰邀約所創作的作品，是首位運用二胡八度定弦於二胡協奏曲的作曲家，這樣的創新與突破，使筆者興起了探討此作品之意。
本文分為五章，包含第一章的緒論，為研究此論文的目的和方向；第二章為介紹關迺忠的生平、創作、工作經歷及本作品的創作背景；第三章將藉由樂曲分析來了解作曲者在創作時所運用到的創作手法；第四章由筆者經由對作品通盤的認識後，融會自身的音樂思維，對樂曲進行深入詮釋探討；第五章結論，經由前面章節的探討，為此論文做出結論。
希望透過此研究，能讓未來的演奏者們能有更多可以參考的依據。也希冀能讓有志於創作八度定弦二胡樂曲的創作者們，能對這少見的定弦型式有更多的認識和啟發，已達成此論文的目的。
"Erhu concerto no.4 – Love and Hatred" is the piece created by Kwan, Nai-Chung in 2008 with the invitation of Yeh ,Tsun (Music director of the Singapore Chinese Orchestra), in addition, Kwan, Nai-Chung is the first composer using erhu tuned in eighths in erhu concerto. This type of innovation and breakthrough has led the interest of the author to explore this fine piece.
This paper is divided into five chapters. Chapter one is the introduction, which states the goal and direction of this study; chapter two is the introduction of Kwan, Nai-Chung’s biography, creation, employment experience and the background of Erhu concerto no.2 – Love and Hatred. Chapter three uses musical analysis to better understand the creation method imposed by composer when creating Love and Hatred. Chapter four is the in-depth interpretation and discussion of the song after the author has comprehensively understood the work of Love and Hatred. Chapter five is the conclusion of the previous chapters.
The goal of this dissertation is to hope through this research the future composers will have more reference to be based on. In addition, also hope for those composers who are interested in creating tuned in eighths erhu music to have better understanding and inspiration of this rarely seen tuned stringed type of music.
