  We show the 't Hooft Equation and the light-front holographic Schr\"odinger
Equation are complementary to each other in governing the transverse and
longitudinal dynamics of colour confinement in quark-antiquark mesons.
Together, they predict remarkably well the light, heavy-light and heavy-heavy
meson spectroscopic data. The universal emerging hadronic scale of light-front
holography, $\kappa \approx 0.5$ GeV, controls the transverse dynamics of
confinement in all mesons. In heavy-heavy mesons, it also coincides numerically
with the 't Hooft coupling which governs longitudinal confinement, thus
reflecting the restoration of manifest 3-dimensional rotational symmetry

High Energy Physics - Phenomenology