  Leading charm production in reaction $\pi^- N \rightarrow DX$ is
discussed.Three experiments at Fermilab and CERN have measured a rather large
enhancement in production rate of leading $D^-$-mesons over nonleading $D^+$.A
good description of these results is obtained in Quark Gluon String Model
(QGSM) if the idea of 'intrinsic charm' is involved. The weight of the
$c\bar{c}$ pairs in the quark sea of colliding hadrons is estimated from the
experimental data. The comparison with other theoretical models is also carried
out.
