A Revisit to the ABS H2 Equation

In this paper we revisit the Adler-Bobenko-Suris H2 equation. The equation is linearly related to $S^{(0,0)}$ and $S^{(1,0)}$ variables in Cauchy matrix scheme. We elaborate coupled quad-system of terms their 3-dimensional consistency, Lax pair, bilinear form continuum limits. It shown that itself satisfies a 9-point lattice limit eigenfunction pair Korteweg-de Vries