3wheels: The checker board had essentially an ILS transmitter fitted to it. It was on a hillside at 390ft elevation and the approach was offset from the runway course by 47 degrees. Thus the approach could be flown in IMC down to a decision height of 675 ft. before a turn to the right to align with the runway was required.
During the times of year when the cloudbase and/or visibility were poor then an approach flown to minimum the checker board would not necessarly be visible at minimum. There was a set of flashing curved strobes which gave a 'lead - in ' to the runway.
For about 80% of the year the visibility and/or cloudbase were above 1,500 ft. and then the checkerboard could be used for visual final placing. In fact it was an accepted practice to "leave the IGS" early and to fly a bit to the north of the IGS course in order to give an easier final turn on to the runway. There was of course also the option from ATC when the weather was really good to fly an abbreviated visual approach up the Western Harbour using Chung Chau, Green Island, Stonecutters Island and then the Checkerboard - this saved about 30 track miles and had the potential to get "rather exciting" if it was not done properly!! ( if you get my drift?!)
Happy days.