  The motion of three bodies can be solved perturbatively when a tightly bound
inner binary is orbited by a distant perturber, giving rise for example to the
well-known Kozai-Lidov oscillations. We propose to study the relativistic
hierarchical three-body orbits by adapting the Effective Field Theory
techniques used in the two-body problem. This allows us to conveniently treat
the inner binary as an effective point-particle, thus reducing the complexity
of the three-body problem to a simpler spinning two-body motion. We present in
details the mapping between the inner binary osculating elements and the
resulting spin of the effective point-particle. Our study builds towards a
derivation of three-body analytic waveforms.
