The paper investigates the large alternmagnetic splitting near the Fermi level in CrSb, a material with collinear alternmagnetism. Alternmagnetism is characterized by momentum-dependent band and spin splitting without net magnetization. The authors use synchrotron-based angle-resolved photoemission spectroscopy (ARPES) and model calculations to uncover a significant alternmagnetic splitting of up to 1.0 eV near the Fermi level in CrSb. They confirm the bulk-type $g$-wave alternmagnetism through systematic three-dimensional $k$-space mapping, revealing the alternmagnetic symmetry and associated nodal planes. The ARPES results are well supported by density functional theory (DFT) calculations. The tight-binding model analysis indicates that the large alternmagnetic splitting arises from strong third-nearest-neighbor hopping mediated by Sb ions, breaking both space-time reversal symmetry and translational spin-rotation symmetry. The high Néel temperature (up to 705 K) and simple spin configuration of CrSb make it a promising material for exploring emergent phenomena and spintronic applications based on alternmagnets.The paper investigates the large alternmagnetic splitting near the Fermi level in CrSb, a material with collinear alternmagnetism. Alternmagnetism is characterized by momentum-dependent band and spin splitting without net magnetization. The authors use synchrotron-based angle-resolved photoemission spectroscopy (ARPES) and model calculations to uncover a significant alternmagnetic splitting of up to 1.0 eV near the Fermi level in CrSb. They confirm the bulk-type $g$-wave alternmagnetism through systematic three-dimensional $k$-space mapping, revealing the alternmagnetic symmetry and associated nodal planes. The ARPES results are well supported by density functional theory (DFT) calculations. The tight-binding model analysis indicates that the large alternmagnetic splitting arises from strong third-nearest-neighbor hopping mediated by Sb ions, breaking both space-time reversal symmetry and translational spin-rotation symmetry. The high Néel temperature (up to 705 K) and simple spin configuration of CrSb make it a promising material for exploring emergent phenomena and spintronic applications based on alternmagnets.