The Kumgang laser, a 4 kW (4 x 0.1 J @ 10 kHz / 8.5 ns) coherent beam combination laser using self-controlled stimulated Brillouin scattering phase conjugation mirrors (SBS-PCMs), is being developed. The front-end (FE) and the pre-amplifier (PA) are completed. The FE produces pulse energy of 0.51mJ and a pulse width of 8.5 ns with a 10 kHz repetition rate (0.51mJ @ 10 kHz / 8.5 ns) and a 95 MHz linewidth. The PA amplifies up to 200 W (20 mJ @ 10 kHz / 8.5 ns) with an input power 5.1 W.