  We extend our model for the pion, which we used previously to calculate its
diagonal structure function, to the off-forward case. The imaginary part of the
off-forward gamma* pi -> gamma* pi scattering amplitude is evaluated in the
chiral limit (m_pi=0) and related to the twist-two and twist-three generalised
parton distributions, H, H3, H3tilde. Non-perturbative effects, linked to the
size of the pion and still preserving gauge invariance, are included.
Remarkable new relations between H, H3 and H3tilde are obtained and discussed.
