  We introduce a categorical analogue of Saito's notion of primitive forms. Let
$W$ denote the potential $\frac{1}{n+1} x^{n+1}$. For the category $MF(W)$ of
matrix factorizations of $W$ we prove that there exists a unique, up to
non-zero constant, categorical primitive form. The corresponding genus zero
categorical Gromov-Witten invariants of $MF(W)$ are shown to match with the
invariants defined through unfolding of singularities of $W$.
