The spectral power distributions of strongly metameric visually matching pairs of lights, at visual fields of 10 degrees and 1.3 degrees and luminances front 0.2-120 cd/m(2), are examined for possible rod participation on the Aguilar-Stiles model, in the visual matches. We develop a method for computing visual jnds of predicted rod intrusion; i.e., an analytical expression for rod mismatch. With this, we compute possible rod mismatch for 922 metameric pairs of lights, each pair pronounced a visual match by one or another of eight normal observers, by using the Trezona expression for pupil diameter or by arbitrarily assigning pupil diameters of 4, 6, 8, or 10 mm. We find some evidence of possible rod participation in the matches, under certain conditions, in small parts of the (brightness)-(fieldsize)-(spectral composition) three-space. On the Aguilar-Stiles model, rod participation is not an appreciable contributor to the troublesome tristimulus errors documented, in earlier parts of this series of articles, to be present at high and low field brightness and at large (10 degrees) and small (1.3 degrees) visual fields.