GEKKO XII is a high-power 12-beam neodymium doped glass laser at the Osaka University's Institute for Laser Engineering completed in 1983, which is used for high energy density physics and inertial confinement fusion research. The name refers to the twelve individual beamlines used to amplify the laser energy. GEKKO is currently being upgraded with the addition of a second "side-by-side" laser, the LFEX (Laser for Fast Ignition Experiment), part of the FIREX-1 program, in order to deliver a 10 kJ pulse of energy to a target in 10 picoseconds, further exploring the fast ignition regime.