  Non-leptonic kaon decays are often described through an effective chiral weak
Hamiltonian, whose couplings ("low-energy constants") encode all
non-perturbative QCD physics. It has recently been suggested that these
low-energy constants could be determined at finite volumes by matching the
non-perturbatively measured three-point correlation functions between the weak
Hamiltonian and two left-handed flavour currents, to analytic predictions
following from chiral perturbation theory. Here we complete the analytic side
in two respects: by inspecting how small ("epsilon-regime") and intermediate or
large ("p-regime") quark masses connect to each other, and by including in the
discussion the two leading Delta I = 1/2 operators. We show that the
epsilon-regime offers a straightforward strategy for disentangling the
coefficients of the Delta I = 1/2 operators, and that in the p-regime
finite-volume effects are significant in these observables once the
pseudoscalar mass M and the box length L are in the regime ML \lsim 5.0.
