A binding system for a touring ski binding has a front jaw device and a rear jaw device for receiving a ski boot. In a descent mode, the front jaw device is open and the rear jaw device is closed, so that a retainer can receive a web of the ski boot, and a lever mechanism can fix a heel part of the ski boot. The rear jaw device with the lever mechanism exerts a contact pressure on the heel part of the ski boot along a boot longitudinal axis (X), so that the web is pressed into a hook system of the front jaw device, and the ski boot is thus secured against translation against the boot longitudinal axis (X).