  We analyse the geodesic E10/K(E10) sigma-model in a level decomposition
w.r.t. the A8xA1 subalgebra of E10, adapted to the bosonic sector of type IIB
supergravity, whose SL(2,R) symmetry is identified with the A1 factor. The
bosonic supergravity equations of motion, when restricted to zeroth and first
order spatial gradients, are shown to match with the sigma-model equations of
motion up to level four. Remarkably, the self-duality of the five-form field
strength is implied by E10 and the matching.
