Early spectroscopic evolution of SN 2024bch (up to +16 days ). Spectra were not corrected for Galactic extinction along the line of sight. The circle with cross, ⊕, symbols mark the position of the main telluric features. Zoom-in panels show the Hβ and He I/NaID regions (at +7 and +8 days for Hβ, and +7, +8, and +16 days for NaID) and Hα, with expansion velocities referred to the rest-frame wavelengths marked with vertical yellow lines. Rest-frame phases refer to the estimated explosion epoch.