The invention relates to a lower tool (1) having a longitudinal-offset measuring device (2), which lower tool (1) is part of a bending tool arrangement for use in a bending press. The lower tool (1) has a tool body (3) having a longitudinal extension (4), in which longitudinal extension (4) a bending recess (5) is provided. The bending recess (5) extends from an upper flat side (6) of the tool body (3) into the latter and is formed at least by two contact surfaces (7). The transition from the upper flat side (6) into the bending recess (5) forms a contact edge (8), which contact edge (8) forms a contact line (9) in the longitudinal extension (4). A sensor (10) for determining a longitudinal offset (18) is arranged in the region of the contact line (9), wherein a sensing portion (11) of the sensor (10) is oriented in the direction of a metal sheet (16) to be bent.