Mortar () and trench mortar was increased and manufacture began of (ALGP, long-range heavy guns); production of ammunition was reduced to increase quality and large orders were placed for aircraft and for gas shells. The growth of French war production by September 1915, enabled the French to attack in two places simultaneously. At the end of June, Joffre discussed strategy with the army group commanders and Pétain, who had been promoted to the command of the Second Army. Foch again advocated a series of limited attacks, particularly in Artois where strategically important railways were relatively close behind the German lines. Castelnau believed that it was still possible to advance through the German defences in one attack and that Champagne was a likely region for such an attempt, if the mistakes made on 9 May could be avoided. Pétain agreed with Foch but doubted that another offensive could quickly be prepared in Artois and was sceptical that any part of the Western Front was free of villages like Souchez and Neuville, which could be fortified and against which, only attacks even more limited than those advocated by Foch were practical. On 8 July, Joffre decided to make the principal attack in Champagne, with a supporting attack in Artois a few days earlier to attract German reserves. Joffre had accepted claims by Castelnau, that up to of ground could be gained in twenty-four hours and rejected a methodical battle, which Ammunition necessary for a methodical battle did not exist and the opportunity to attack the Germans, when so many divisions had been moved to the eastern front, could not be wasted. The offensive had been fought with unprecedented refinements of tactics and supply. Amendments to Note 5779 were suggested, to cover items like the use of grenades in two days by the 53rd Division and the importance of attention to detail; Pétain of XXXIII Corps had ensured accurate preparatory bombardments and the tactical reflections written by Pétain were added to the thinking in Note 5779. The ideal characteristics of a network of jumping-off trenches and the time and labour necessary to build it were laid down, so that troops could advance simultaneously and reserve troops could be protected as they moved forward. Pétain wrote the plan for the , for the offensive of 25 September and his views were circulated through the French and British armies. The autumn offensive was fought as