This one tool proves we are serious about acoustic guitar repairs.
For accuracy, the jig relies on a 48 inch long aluminum ruler captured inter the top of the jig. You can see the edge of the ruler sticking out 1/4 inch beside the plane.
The mahogany block on top is a clamp with rubber no-slip material. This ensures the top plank (shown here) cannot move or slide around.
The plane is the superb Veritas Shooting Plane ($340 and up).