The kinetic energy release and its variation with laser polarization in laser fragmentation of Rydberg Matter clusters is studied with a power density < 10(9) W cm(-2). The fragment ions observed are K-N(+) with N = 1, 2, 3, 4 and 7. The excess kinetic energy of the fragment ions observed with the laser polarization in the detector plane is approximately 0.4 eV, The fragmentation is sensitive to the external field strength at 1-3 V cm(-1). The interionic distance in the Coulomb explosions is 3 nm. The polarization effect for ns pulses indicates slow cluster rotation and a cluster size of > 0.3 mu m.