  We report measurements of time dependent decay rates for $B^0 \to
D^{(*)-}\pi^+$ decays and extraction of CP violation parameters that depend on
$\phi_3$. Using fully reconstructed $D^{(*)}\pi$ events and partially
reconstructed $D^{*}\pi$ events from a data sample that contains 386 million
$B\bar{B}$ pairs that was collected near the $\Upsilon(4S)$ resonance, with the
Belle detector at the KEKB asymmetric energy $e^+ e^-$ collider, we obtain the
CP violation parameters $S^+ (D^{(*)}\pi)$ and $S^- (D^{(*)}\pi)$. We obtain
  $S^+ (D^* \pi) = 0.049 \pm 0.020(\mathrm{stat}) \pm 0.011(\mathrm{sys})$,
  $S^- (D^* \pi) = 0.031 \pm 0.019(\mathrm{stat}) \pm 0.011(\mathrm{sys})$, and
  $S^+ (D \pi) = 0.031 \pm 0.030(\mathrm{stat}) \pm 0.012(\mathrm{sys})$,
  $S^- (D \pi) = 0.068 \pm 0.029(\mathrm{stat}) \pm 0.012(\mathrm{sys})$.
  These results are an indication of CP violation in $B^0 \to D^{*-}\pi^+$ and
$B^0 \to D^- \pi^+$ decays at the $2.5 \sigma$ and $2.2 \sigma$ levels,
respectively. If we use the values of $R_{D^{(*)}\pi}$ that are derived using
assumptions of factorization and SU(3) symmetry, the branching fraction
measurements for the $D_s^{(*)} \pi$ modes, and lattice QCD calculations, we
can restrict the allowed region of $|\sin (2\phi_1 + \phi_3)|$ to be above 0.44
and 0.52 at 68% confidence level from the $D^* \pi$ and $D \pi$ modes,
respectively.
