  SS 433 is a microquasar, a stellar binary system with collimated relativistic
jets. We observed SS 433 in gamma rays using the High Energy Stereoscopic
System (H.E.S.S.), finding an energy-dependent shift in the apparent position
of the gamma-ray emission of the parsec-scale jets. These observations trace
the energetic electron population and indicate the gamma rays are produced by
inverse-Compton scattering. Modelling of the energy-dependent gamma-ray
morphology constrains the location of particle acceleration and requires an
abrupt deceleration of the jet flow. We infer the presence of shocks on either
side of the binary system at distances of 25 to 30 parsecs and conclude that
self-collimation of the precessing jets forms the shocks, which then
efficiently accelerate electrons.
