Ichijyo introduced (a, b, J)-manifolds as a special class of generalized Randers manifolds. We introduce generalized (a, b, J)-manifolds. A partial negative answer to Ichijyo's open problem on nearly Kahler Finsler manifolds is given. The condition under which generalized (a, b, J)-manifolds are Berwaldian is obtained. Finally, we prove that under a mild assumption a nearly Kahler Finsler manifold is Landsbergian.