Simulations of the dynamical effects of 10 000 asymmetric SNe on BH binary systems. The initial pre-SN system contains two 50 M_⊙ stars in a binary with an orbital period of 2.0 days. During the formation of a BH, it is assumed that 10 M_⊙ is lost instantaneously and a kick velocity is imparted with a magnitude between 0−300 km s^-1, drawn from a flat distribution and an isotropic (random) distribution of kick directions. The upper left panel shows the resulting post-SN systems in the orbital period-eccentricity plane. The colours indicate the merger time of the post-SN system as a result of gravitational-wave radiation (see the distribution in the upper right panel). The lower panels show the distributions in orbital period and eccentricity of the post-SN binaries. The case of a purely symmetric SN (no kick) is indicated with a black dot in all panels.