  In this paper, we study the unicorn's Landsberg problem from an intrinsic
point of view. Precisely, we investigate a coordinate-free proof of Numata's
theorem on Landsberg spaces of scalar curvature. In other words, following the
pullback approach to Finsler geometry, we prove that all Landsberg spaces of
dimension $n\geq 3$ of non-zero scalar curvature are Riemannian spaces of
constant curvature.
