In summary, we have or presented the first crystal structure of a free-base corrole anion. The structure exhibits localized NH hydrogens on a pair of opposite pyrrole rings, which we may designate as rings A and C, or equivalently as B and D. A key feature of the structure is the short-strong N-H...N hydrogen bond within each dipyrrin moiety on either side of the molecular pseudo-C2 axis through the C10 meso-carbon. DFT calculations identify AC and BD as equienergetic global minima with the two cis tautomers AD and BC only 4-7 kcal/mol above the global minima (in terms of electronic energy). In terms of free energy, however, the cis tautomers are just above or essentially flush with the trans-to-cis barrier heights. Accordingly, the hydrogen bonds in free-base corrole anion qualify as or closely approach low-barrier hydrogen bonds. Proton migration across the molecular pseudo-C2 axis, on the other hand, entails much higher activation energies of > 20 kcal/mol. Given the overall mobility of the lowbarrier hydrogen bond system, we find it gratifying that our low-temperature crystal structure has revealed a single, ordered tautomer.