The use of Soviet tanks in the Spanish Civil War provides an intriguing example of the potential and problems of innovation in military technology. As the first major employment of armor since the end of World War I, the Spanish Civil War was seen by some observers as offering valuable lessons in the debate over the future role of tanks and tank warfare. Yet at the same time, other observers questioned whether the lessons had relevance to major armies due to the small scale of tank employment in Spain, the poor tactics employed, and the unique conditions of the Spanish experience. In the case of the Red Army, the Spanish Civil War experience did have some important consequences in tank technology, but on the tactical side, many lessons were ignored, distorted, or misunderstood.
In the face of German and Italian military aid to Franco's insurgent Nationalist forces, Stalin decided to send military aid to the Republican forces in the Spanish Civil War. The first shipment of tanks and tank specialists left for Spain in September 1936. The cargo ship Komsomol arrived at the port of Cartagena on 12 October 1936 with a shipment of 50 T-26 light tanks and 51 "volunteer" tank specialists. In the meantime, the Soviet military attach?at the Madrid embassy, Kombrig Vladimir Gorev, had arranged for the creation of a training center near the town of Archene in Mursia, about 90 km. from the port. The Soviet government did not plan to provide crews for the tanks sent to Spain, but rather to train Spanish personnel to operate them. Archene became the main training and technical center for the Republican tank force for much of the war.
The T-26 light tank was the standard infantry tank in Red Army service at the time, and the most widely produced Soviet tank of the inter-war period. Indeed, it was manufactured in larger numbers than all of the other tanks of the world combined of the 1930s. The T-26 was a license-built copy of the British Vickers 6-ton light tank, but with a Soviet designed turret and gun. The Red Army followed the common European practice of the day, employing several different types of tanks for specific roles. While the slow T-26 tank was intended to provide support to Red Army rifle divisions, the BT-5 "fast tank" was intended for the cavalry and deep exploitation role, much like the contemporary British cruiser tanks. Due to the nature of the fighting, the T-26 was the main type of tank sent to Spain during the war, accounting for 281 of the 331 tanks sent to Spain. The T-26 was not ideal for infantry support. It was thinly armored, and vulnerable to contemporary anti-tank guns. In contrast, the newer generation of infantry tanks such as the French Renault R-35 and British Matilda I were significantly better armored. The T-26 had an advantage in firepower, however, being armed with a dual-purpose 45mm gun that was more versatile than the armament on British or French infantry tanks of the period.
The initial training program at Archene was headed by Kombrig Semen M. Krivoshein. Although the initial plans were to confine the use of Soviet personnel to training, by the end of October, the situation for the Republican forces around Madrid was becoming so desperate that the Soviet attach?V. Gorev was authorized to form some ad hoc combat formations from the Archene training center and send them to reinforce the Madrid front. At least three small groups were dispatched to the front, one headed by Komrot A. Novak with six BA-3 armored cars and seven T-26 tanks, a Spanish tank platoon under Major P. Villakansas, and a reinforced company-sized formation under Kombat Paul Arman. The two first groups went into action on the night of 27 October 1936 with little effect. The first significant action by the Republican tank force occurred on the morning of 29 October by Arman's partially formed 1st Tank Battalion.
