Non-factorizable contributions in nonleptonic weak interactions of K mesons

K → ππ, KL-KS mass difference and KL → γγ(∗) are studied systematically by decomposing their amplitude into a sum of factorizable and nonfactorizable ones. The former is calculated by using the naive factorization while the latter is assumed to be dominated by dynamical contributions of various hadron states. Non-factorizable amplitudes for the K → ππ decays are estimated by using a hard pion approximation in the infinite momentum frame. Long distance non-factorizable contributions to the KL-KS mass difference is dominated by those of pseudo scalar meson poles and ππ intermediate states. The amplitude for the KL → γγ(∗) is given by a sum of pole contributions of pseudo scalar mesons in the s-channel and K meson in the crossed channel. By fitting the results on the K → ππ, KL-KS mass difference and KL → γγ to the observations, values of unknown parameters involved are estimated and then, by using the resulting values of these parameters, the form factor for the Dalitz decays of KL and their rates are predicted. The results are compared with the existing data.