The blooding of 38th (Welsh) Division at Mametz Wood on the Somme in July 1916 remains an iconic and controversial episode in both Wales’s First World War history and its legacy. It has come to stand as part-proxy for the battlefield experience of Welsh troops in general. The action, though ultimately successful, was costly. Many observers judged the Division’s performance disappointing. Drawing on a range of comparative historiography, modern scholarship and archival research, this essay reassesses 38th’s record in the battle.