  Early phase optical spectra of aspherical jet-like supernovae (SNe) are
presented. We focus on energetic core-collapse SNe, or hypernovae. Based on
hydrodynamic and nucleosynthetic models, radiative transfer in SN atmosphere is
solved with a multi-dimensional Monte-Carlo radiative transfer code, SAMURAI.
Since the luminosity is boosted in the jet direction, the temperature there is
higher than in the equatorial plane by ~ 2,000 K. This causes anisotropic
ionization in the ejecta. Emergent spectra are different depending on viewing
angle, reflecting both aspherical abundance distribution and anisotropic
ionization. Spectra computed with an aspherical explosion model with kinetic
energy 20 x 10^{51} ergs are compatible with those of the Type Ic SN 1998bw if
~ 10-20% of the synthesized metals are mixed out to higher velocities. The
simulations enable us to predict the properties of off-axis hypernovae. Even if
an aspherical hypernova explosion is observed from the side, it should show
hypernova-like spectra but with some differences in the line velocity, the
width of the Fe absorptions and the strength of the Na I line.
