The combat of Yanzi (1 August 1813) saw a small Spanish force badly disrupt Soult’s retreat down the Bidassoa valley in the aftermath of his defeat at the second battle of Sorauren.
In the aftermath of his defeat at the second battle of Sorauren, Soult decided to move his main force west, then retreat north over the Peurto de Arraiz heading for Sanesteban, where the Bidassoa turns north, after flowing west for several miles. Wellington assumed that he was going to use the Velate Pass, further to the east, and sent most of his troops along that route, or on routes even further to the east. Only Lord Dalhousie’s 7th Division was ordered to follow the Peurto de Arraiz, although on 31 July Hill’s troops, who had fought at Beunza, bore the brunt of an attack on the French rearguard (combat of Venta de Urroz or Donna Maria), before obeying Wellington’s orders to move to the Velate.
By the end of 31 July Soult’s forces were concentrated around Sanesteban, where the Bidassoa turned north, flowing through a narrow valley. His plan was to follow the road up the valley until he reached a side valley that ran east past the village of Echalar to the col de Echalar, on the Franco-Spanish border. The road ran along the eastern side of the river, which runs through a narrow valley on this stretch. Wellington’s leading troops were around Elizondo, seven miles to the east, while Dalhousie spent the night at the top of the Arraiz pass.
Soult’s plan was to move north down the Bidassoa valley for just over seven miles, until he reached a side valley that ran east to Echalar, and from there to the Col de Echalar, on the Franco-Spanish border. One mile to the south of the key road junction, another side valley runs into the Bidassoa, this time coming from the west. Just over a mile up this valley is the village of Yanzi (modern Igantzi). A road ran east from the village down to the Bidassoa, and then crossed the river over the bridge of Yanzi to join the main road. The French didn’t actually need to cross this bridge, as they were concentrated on the eastern side of the river.
The Allies only had a handful of troops watching the bridge, two companies of troops provided by Longa. On the previous day a battalion from Barcena’s division was moved to the village, placing them a mile to the west of the river. Given the amount of confusion the two companies caused, Soult was lucky that this battalion hadn’t been ordered to dig in around the bridge.
Soult began his march at 2.30am on 1 August. His column was headed by one infantry battalion from the 120th Line from Reille’s ‘corps’. Next was Treillard’s six regiments of Dragoons, followed by Lamartiniere’s division, then the wounded, the survivors of Maucune’s division and Pierre Soult’s cavalry. Drouet’s ‘corps’ was next in line, with Abbé’s division first (having formed the rearguard on the previous day), them Maransin and finally Darmagnac. Clausel’s ‘corps’ formed the rearguard, with orders to watch the routes from the east and the south.
The French appear not to have sent any scouts ahead of the main force, for the battalion from the 120th was caught by surprise when the Spanish opened fire from the bridge. The French soon realised that the Spanish force was very small, and the 120th attacked the bridge. They quickly forced the Spanish to retreat, clearing the route. However the noise of the fighting caused a panic in the Dragoons who were next in line, and they fled south, almost running down Reille and his staff. The entire French column was forced to stop to sort out the mess.
Reille responded by sending the 2nd Leger along a footpath on the slopes to the east of the road to find out what had happened. By the time they arrived at the bridge, the Spanish had gone. The 120th and 2nd Leger then resumed their march north, followed by the Dragoons, but leaving nobody to guard the bridge.
Once the French had moved on, the Spanish moved back to the river. This time they took a position half a mile from the bridge on the west bank of the river, from where they fired across the ravine at the French cavalry. This was the situation when Reille arrived in person. He ordered the next infantry unit that passed, the 2nd Battalion of the 120th Foot, to swing out of the line, take up a position on the slopes to the east of the road, and pin the Spanish down. Another battalion was sent across the bridge and then pushed upstream to attack the Spanish. Once again the Spanish were forced to retreat away from the road, leaving the French free to resume their march north. The dragoons and Lamartiniere’s infantry then filed past the bridge. Reille joined them, but this time took the precaution of leaving an infantry battalion from the 118th Line at the bridge.
The two Spanish companies that had been posted at the bridge were now joined by the battalion from the Regiment of the Asturias that had been posted at Yanzi village. They attacked the bridge, pushed back the French, and attacked the passing baggage train. The baggage train turned back, and ran into the wounded and Maucune’s division, causing yet another delay to the French move. This time the delay lasted for two hours. Maucune’s battered division was the next French combat unit to arrive, but they were too weak to push the Spanish away, and even Maucune had to admit that his division ‘fought feebly’, and only lost 30 men. Eventually Abbé’s men from Drouet’s ‘corps’ reached the bridge. He managed to organise an attack by four or five battalions, and eventually the 64th Line cleared the bridge once again. This attack cost them 9 officers, and around 200 men. In a repeat of Reille’s behaviour, Abbé then left two battalions to guard the bridge and the hill to its west, before leaving with the rest of his troops.
The French had one final scare. Darmagnac’s division, which now formed the army’s rearguard after Vandermaesen’s had abandoned the fight and fled across the hills towards Echalar, had just reached the bridge, when the leading troops from the British Light Division finally arrived on the scene, after several days of frustratingly pointless marches. The most advanced troops from the Light Division carried out one last attack, and recaptured the bridge, but by then the French column had passed by, and the chance for a major victory was gone. Even so the British took around 1,000 prisoners, mainly stragglers.
Soult had escaped from the worst danger. He now drew up his army on the hills above Echalar, and prepared to try and defend the French border. However when the British attacked on the following day the French proved to be unable to hold onto their new position, and were forced to retreat back over the border (combat of Echalar, 2 August 1813).