A notched batten is one of the best jigs you can make to help in hand planning. This simple thin hardwood strip has a hoof-shaped notch at its end and is used to prevent boards from shifting during planing. The way it works is pretty simple. First, tuck your board against the bench’s planing stop, then introduce the notched batten to the rear outer corner of the board and clamp it in place using a hold fast or a long reach clamp. Once planning begins, the workpiece will be pressed (forward) toward the planing stop and (sideways) against the notched batten and will not be able to move, hence making planing both an effective and predictable process.
The notched batten that I built recently is based on traditional designs but with one deviation. Instead of only one centered notch on one end, I created two: One notch is generic (a), whereas the notch on the opposite end (b) is pivoted to an asymmetrical position.