  We present SiO J=8-7 (347.3 GHz) observations towards HH 212 using the ASTE
telescope. Our observations with a 22''-diameter beam show that the SiO
emission is highly concentrated within 1' of the driving source. We carefully
compare the SiO observations with archival H_2 1-0 S(1) images and published
H_2 echelle spectra. We find that, although the SiO velocities closely match
the radial velocities seen in H_2, the distribution of H_2 and SiO emission
differ markedly. We attribute the latter to the different excitation conditions
required for H_2 and SiO emission, particularly the higher critical density
(n_H2 ~10^8 cm^-3) of the SiO J=8-7 emission. The kinematic similarities imply
that the H_2 and SiO are associated with the same internal working surfaces. We
conclude that the SiO J=8-7 emission has a potential to probe the jet/wind
launching region through interferometric observations in the future,
particularly for the youngest, most deeply embedded protostars where IR
observations are not possible.
