The approach to runway 13 at Kai Tak was not exactly low tech. The landing system used was called Instrument Guidance System (IGS). The system uses ILS components but is offset from the landing direction by 47 degrees, therefore necessitating a visual right turn to line up with the runway after reaching decision height.
The approach was identical to any standard ILS, all the way until the Middle Marker (MM) when the fun really begins. Visual flight must be established by the MM and the pilot in control must take over manually to complete the turn. The hill on which the checkerboard was painted is where the IGS transmitter was located (the red and white mast you see in photos), and represents the physical end of the instrument approach. The checkerboard is there to give pilots a visual reference of where they should NOT be.
In fact, the standard approach charts to Kai Tak contains the following terse warning : "Continued flight on the IGS flight path after passing the MM will result in loss of terrain clearance"