Quantum Chromodynamics (QCD) is one of the most successful theories in modern physics to explain the binding of nucleons inside a nucleus . But why is it so hard? In this video, I explain the difficulty of QCD by building intuition step by step—starting from the familiar idea of the strong nuclear force at the high school level, moving through Yukawa theory, and finally reaching the deeper structure of QCD. You will understand: • Why the nuclear force was first modeled using Yukawa theory • How