org-hide-leading-stars

org-hide-leading-stars is a variable defined in `org.el'.
Its value is

nil

Documentation:
Non-nil means hide the first N-1 stars in a headline.
This works by using the face `org-hide' for these stars. This
face is white for a light background, and black for a dark
background. You may have to customize the face `org-hide' to
make this work.
Changing it requires restart of `font-lock-mode' to become effective
also in regions already fontified.
You may also set this on a per-file basis by adding one of the following
lines to the buffer:

#+STARTUP: hidestars
#+STARTUP: showstars

You can customize this variable.