AbstractKnoop and Vickers indentation cracks have frequently been used as model‘precracks’in ceramic bend specimens for fracture toughness (K1c) determination. Indentation residual stress reduces the measured K1cbut can be removed or accounted for by grinding, annealing, or modelling. Values of K1care obtained for four materials using Vickers indentations and an improved stress intensity factor. Methods for residual stress removal or incorporation are compared, and the most reliable stress removal alternative is identifiedfor each material.MST/3242