According to ASK4BEAUTY.COM, the plan studied by the national command initially provided for the termination of the pocket and the conquest of the Cantabrian watershed which runs parallel to a short distance from the base of the pocket itself; at a later time the attacking columns had to proceed swiftly and decisively on Santander.
The battle, preceded by rigorous air and artillery preparation, began on 14 August. While in the west the national forces advanced north-east towards Reinosa, in the east the legionaries of the “23rd March”, occupied the hills of Raspanera, turned south to occupy the Bricia mountains and thus protect the left flank of the legionary division. “Black flames”, which advancing in a north-west direction, managed to reach, after violent fighting, the Cantabrian watershed in Puerto de Escudo; immediately after the “Littorio” legionary division, assisted by a mixed rapid detachment (mechanized vehicles and cavalry), breaking into the gap left open by the divergent attack of the other two divisions, it advanced westwards, spreading over the plain of Corconte and occupying the road junctions of Arija and La Población. In just three days this first phase of the maneuver could be considered closed.
The second phase of the battle took place from 19 to 26 August; to it, in addition to the forces already mentioned, perhaps nationals took part in the west operating along the Río Zaja with the task of cutting communications between the Santanderino and the neighboring Asturias, to the east national and legionary units, including the “Black Arrows” brigade, charged with completing the winding of the extreme section of the northern front from the south and east. In the center, the two legionary divisions “Fiamme neri” (on the right for the Pisuena valley) and “Littorio” (on the left, along the Pas valley) despite the adverse weather conditions and the tenacious resistance of the enemy, proceeded decisively towards the north; one by one or by maneuver or because they were annihilated by rapid concentrations of artillery and aerial bombardments, the enemy strongholds were overtaken by the legionary troops, who arrived in sight of Santander on the evening of the 25th. On the morning of the 26th the city surrendered.
Immediately afterwards, operations for the conquest of Gijón began. Before the fall of Santander, on 24 August the national troops, made up of the Navarra brigades under the command of General Solchaga, who, as we have already seen, had the task of cutting communications between Santanderino and Asturias, had occupied Torrelavega and therefore, with a change of front to the west, they had put themselves in a position to invade Asturias following the beam of coastal communications. Other forces made up of the VIII army corps (general group Aranda) were concentrated further south-west, ready to point towards the passes of the Cantabrian watershed as soon as the forces of the Solchaga group were in a position to start the march on Gijón.
This hope, however, was disappointed by the troops of Generals Solchaga and Aranda. Having forced the Potes line in September and the Sella line in October, the nationals occupied Villaviciosa and Infiesto on 19 October, and entered Gijón on 21 October, which had rebelled against government forces.
With the collapse of the red Asturian front, the great battle that began on March 31 in the northern sector ended; the three phases of it, which bear the names of Bilbao, Santander and Giójn, lasted respectively: 81, 12 and 58 days.
The balance of this victorious operational cycle can be summarized as follows: complete elimination of the northern front and complete conquest of the rich industrial and mining areas of Biscay and Asturias; destruction of an opposing army of over 150,000 men; capture of about 100,000 prisoners and an enormous spoils of war: hundreds of cannons, dozens of tanks, thousands of machine guns, etc.; complete availability, for operations on other fronts, of the air mass, of the artillery and of the 150 battalions engaged until then on the northern front, as well as of the entire national fleet for the blockade of the Mediterranean coasts of government Spain.
The counter-offensives of the government. – Throughout the period from April to October 1937, the Republicans, with the obvious aim of forcing the nationals to ease the pressure in Biscay and Asturias, had carried out numerous offensive bets on other sectors of the front.
In April, attacks were launched in the regions of Huesca, Teruel, Oviedo and Madrid; in May on the Sierra Guadarrama front and subsequently in the Huesca sector, but without appreciable results.
With the fall of Bilbao, and while the maneuver on Santander was already beginning, a new vigorous offensive was carried out in the Madrid sector; this carefully prepared operation was attended by over 50,000 men (including the best troops made up of the international brigades), 200 pieces of various calibers, 150 tanks and 200 airplanes.
The plan included a demonstration action to the north-east of Toledo and two violent blows of the mallet respectively to the west and south of Madrid, having the city of Navalcarnero, 30 km as a common goal. southwest of the capital.
The action began on 6 July: the attack to the south of Madrid was immediately stopped, while the one to the west was initially able to penetrate for about 15-16 km. in the positions of the national team reaching Brunete. On 11 July the nationals led first by General Varela and then personally by General Franco began a vigorous counterattack; the reconquest of Brunete on 24 July marked the end of the action attempted by the government troops and which gave them results that were certainly not adequate for the serious losses suffered: 30,000 men including dead, wounded and prisoners, various batteries, hundreds of machine guns and 65 tanks armed lost, 110 airplanes shot down. Other offensives attempted by the republicans in July and August in the sector of Teruel and in Aragon and in the sector of Zaragoza; this
Also in this offensive the republican troops obtained at first some success, especially with the conquest of Belatite (3 September) south of Zaragoza, but the timely arrival of national reinforcements from the Biscay front, made available after the capture of Santander, it allowed Franco’s troops to re-establish the position as it was before the government attack. For the whole of September and for the whole of October the pressure of the republicans in the north and south of the Ebro continued, but without concrete results.