We perform the Hamiltonian reduction of three dimensional Einstein gravity with negative cosmological constant under constraints imposed by near horizon boundary conditions. The theory reduces to a Floreanini-Jackiw type scalar field theory on the horizon, where the scalar zero modes capture the global black hole charges. The near horizon Hamiltonian is a total derivative term, which explains the softness of all oscillator modes of the scalar field. We find also a (Korteweg-de Vries) hierarchy of modified boundary conditions that we use to lift the degeneracy of the soft hair excitations on the horizon. Contents arXiv:1906.10694v2 [hep-th] 9 Jul 2019 SciPost Physics Submission B Gelfand-Dikii differential polynomials and Hamiltonians 24 References 26with a i max ,N denoting the number for the largest value of i = i max that leads to non-vanishing a i,N within a given set {a i,N }, and h {a i,N } are rational coefficients for each of these sets. Explicit results for N = 5, 6, 7 are H nl 5 = − 5 36 J 4 + 5 63 J 3H nl 6 = − 5 6