Next, we'll turn our attention to cutting the cornhole in the game board. We'll need a true, six-inch diameter circle cut precisely 8-7/8" down from the top of the playing surface, centered horizontally (at 11-3/4" across the board). See the top view on page 1 of the Free Woodworking Plans you downloaded in step 1.
There are a number of possible choices for cutting this circle. One could simply draw the arc using a compass and cut it out by hand with a jigsaw, but I felt this choice was a little too imprecise. You could also choose to drill it out with a drill press and an adjustable, wide-cutting bit.
However, my choice was to use a small router equipped with a straight bit and a circle-cutting jig. This method allowed me to cut the hole precisely where I wanted, and left a perfect circle behind. If you choose to employ this method, don't try to make the entire cut in one pass. Instead, make the cut in four or five passes so as to not overwork the router or cause the bit to burn.