  Accretion conditions and morphologies of X-ray transients containing neutron
stars are still poorly understood. Circinus X-1 is an enigmatic case where we
observe X-ray flux changes covering four orders of magnitude. We observed
Circinus X-1 several times at its very lowest X-ray flux using the high energy
transmission grating spectrometer on board the Chandra X-ray Observatory. At a
flux of 1.8$\times10^{-11}$ \ergcm we observed a single 1.6 keV blackbody
spectrum. The observed continuum luminosity of 10$^{35}$ \ergsec is about two
orders of magnitude too low to explain the observed photoionized luminosity
suggesting a much more complex structure of the X-ray source which is partially
or entirely obscured as had been previously suggested. This affects most
emissions from the accretion disk including previously observed accretion disk
coronal line emissions. Instead, the strongest observed photoionized lines are
blueshifted by about $\sim 400$ \kms\ and we suggest that they originate in the
ionized wind of a B5Ia supergaint companion supporting a previous
identification. The neutron star in Cir X-1 is very young and should have a
high magnetic field. At the observed luminosity the emission radius of the
blackbody is small enough to be associated with the accretion hot spot as the
X-ray emitting region. The small emission radius then points to a field
strength below $10^{12}$ G which would be consistent with the observation of
occasional type I X-ray bursts at high magnetic fields. We discuss Cir X-1 in
the context of being a high-mass X-ray binary with some emphasis on a possible
Be-star X-ray binary nature.
