Although, the full-CI algorithm is not directly useful beyond academic interest, for its aforementioned exponential complexity, it is directly useful to calibrate new hypothesises/approximations to the Many-Body Schrödinger Equation, that may be useful. Our goal is to reduce CI theory into a game, combinatorics followed by a set of rules, and with it to construct a Hamiltonian from the subset of Slater-Determinants Λ CI ⊂ Λ FCI .