The German attack on Lagnicourt (Unternehmen Sturmbock [Operation Battering Ram]) on 15 April 1917 was a military operation on the Western Front during the First World War. Four German divisions conducted a spoiling attack on the positions of the 1st Anzac Corps of the British Fifth Army. The attack was intended to delay the advance of the Fifth Army towards the Hindenburg Line, inflict casualties and destroy as much equipment, particularly artillery, as possible.