The old Sabatier horn handled plat du semele knives were hand forged in the 1890's in Thiers France on water powered martinet trip hammers and ground on water powered stone wheels. This style of forging is very old and the origins of the bolster can be seen in the bulge at the beginning of the tang/end of heel. As the blade is forged it is flipped around to forge the tang which leaves a thicker area. This would often be forged down and ground off but at one point it became a indicator of quality work by forging it thicker and then grinding it into a graceful shape. These hand forged plat du semelle were the high quality line of slightly less expensive work knives.