similar marks to a soft hammer. Soft hammer finished pieces are usually balanced and symmetrical, and can be relatively smooth. Soft hammer works first appeared in the Acheulean period, allowing tools with these markings to be used as a post quem estimation, but with no greater precision. The main advantage of a soft hammer is that a flintknapper is able to remove broader, thinner flakes with barely developed heels, which allows a cutting edge to be maintained or even improved with minimal raw material wastage. However, a high-quality raw material is required to make their use effective. No studies compare the two methods in terms of yield per unit weight of raw material, or the difference in energy use. The use of a soft hammer requires greater use of force by the flintknapper and a steeper learning curve, although it offers more flakes for less raw material. Soft hammer only Hand axes made using only a soft hammer are much less common. In most cases at least initial work was done with a hard hammer, before subsequent flaking with a soft hammer erased all vestiges of that work. A soft hammer is not suitable for all types of percussion platform and it cannot be used on certain types of raw material. It is, therefore, necessary to start with a hard hammer or with a flake as a core as its edge will be fragile (flat, smooth pebbles are also useful). This means that although it was possible to manufacture a hand axe using a soft hammer, it is reasonable to suppose that a hard hammer was used to prepare a blank followed by one or more phases of retouching to finish the piece. However, the degree of separation between the phases is not certain, as the work could have been carried out in one operation. Working with a soft hammer allows a knapper greater control of the knapping and reduces waste of the raw material, allowing the production of longer, sharper, more uniform edges that will increase the tool's working life. Hand axes made with a soft hammer are usually more symmetrical and smooth, with rectilinear edges and shallow indentations that are broad and smooth so that it is difficult to distinguish where one flake starts and another ends. They generally have a regular biconvex cross-section and the intersection of the two faces forms an edge with an acute angle,