  We study the six-particle amplitude in planar $\mathcal{N} = 4$ super
Yang-Mills theory in the double scaling (DS) limit, the only nontrivial
codimension-one boundary of its positive kinematic region. We construct the
relevant function space, which is significantly constrained due to the extended
Steinmann relations, up to weight 13 in coproduct form, and up to weight 12 as
an explicit polylogarithmic representation. Expanding the latter in the
collinear boundary of the DS limit, and using the Pentagon Operator Product
Expansion, we compute the non-divergent coefficient of a certain component of
the Next-to-Maximally-Helicity-Violating amplitude through weight 12 and eight
loops. We also specialize our results to the overlapping origin limit,
observing a general pattern for its leading divergences.
