The US is leading the way in this type of combined arms training at a facility in Germany, where Ukrainian units are taught how to better co-ordinate company and battalion-sized formations in battle. But Washington’s promise to supply M1 Abrams tanks will add extra complexities to Kyiv’s operations, given these have differing abilities and logistical requirements to the Leopard 2s. Modern combined arms operations have their origins in the later years of the first world war, when imperial Germany devised new tactics to overcome the artillery-dominated Western Front. Ukraine’s allies are now hoping these tactics will help Kyiv prevail in the grinding attritional fight against Russia.