Review of the ɣ3π chiral anomaly

Theoretical descriptions and experimental tests of anomalies are crucial for the development of consistent quantum field theory, wherein anomalies emerge as essential features. The process $\gamma \pi\to \pi\pi$, driven by its abnormal intrinsic parity, appears in the anomalous sector of low-energy quantum chromodynamics (QCD). We briefly review the recent theoretical developments underlying this chiral anomaly, focusing on its extraction based on dispersion relations, lattice QCD, and from the crossed channel $\gamma^* \to 3\pi$.