Copper tools were first used in the Early Dynastic period, from about 3000 BC. As metal technology improved, bronze became the metal used for most tools as it was harder than copper. The adze was an essential component of the woodworker's tool kit. It was used to dress the wood, after its basic shape had been produced using a saw or axe. Unlike the axe, the blade of the adze is set at right angles to the handle, so that, in use, the cutting edge is horizontal rather than vertical. Considerable dexterity was needed to control the depth of the cuts, so that rough edges could be smoothed away.Adzes were also used in a religious context, in the funeral ritual. The Opening of the Mouth Ceremony took place at the tomb entrance. The human-shaped coffin, placed in an upright position, had its 'mouth' ritually opened with an adze. This allowed the deceased to breathe and to receive the food offerings which would sustain him in the Afterlife. The ceremony was usually performed by the eldest son of the deceased, who thereby became his or her heir.