  We present Very Large Telescope optical spectra of the black hole candidate
X-ray binary MAXI J1836-194 at the onset of its 2011 outburst. Although the
spectrum was taken at the beginning of the outburst and contains a significant
contribution from the optically-thin synchrotron emission that originates in
the radio jet, we find that the accretion disk was already large and bright.
Single-peaked, narrow H$\alpha$ and He II $\lambda$4686 lines imply the most
face-on accretion disk observed in a black hole low-mass X-ray binary to date,
with an inclination angle between 4$^{\circ}$ and 15$^{\circ}$, assuming a
black hole mass of between 5 M$_\odot$ and 12 M$_\odot$, for distances of
between 4 and 10 kpc. We use New Technology Telescope observations of the
system in quiescence to place strong upper limits on the mass and radius of the
donor star and the orbital period. The donor is a main sequence star with a
mass < 0.65 M$_{\odot}$ and a radius < 0.59 R$_{\odot}$ with an orbital period
of < 4.9 hours. From those values and Roche lobe geometry constraints we find
that the compact object must be >1.9 M$_{\odot}$ if the system is located 4 kpc
away and >7.0 M$_{\odot}$ at 10 kpc.
