  A compact, few-parametric, physically adequate, 3-term variational trial
function is used to calculate with high accuracy the energy of the ground state
${}^3\Pi_u$ of the hydrogen molecule ${\rm H}_2$ in strong magnetic field ${\bf
B}$ in the range $5\times10^{10}\, {\rm G} \leq B \leq 10^{13}\,$G. The nuclei
(protons) are assumed as infinitely massive (BO appproximation of zero order)
and situated along the magnetic field line (parallel configuration).
