The command wanted to compare their new ships with the latest foreign contemporaries; they noted that all other battleships carried their main armament forward and aft, and several of them used dedicated high and low-angle guns for their secondary batteries. The 130 mm dual-purpose guns used on the "Dunkerque"s were proving to be troublesome in service, and the command wanted to determine whether the arrangement would be suitable for future construction. "Vice-Amiral" François Darlan, who had by now replaced Durand-Viel as Chief of Staff, issued a request for studies on 2 December 1937 with the requirements that the proposals be based on the "Richelieu" design, armed with eight or nine 380 mm guns in quadruple or triple turrets, equipped with a secondary battery of 152 mm or 130 mm dual-purpose guns or a mixed battery of 152 mm and 100 mm guns, and with armor on the same scale as "Richelieu". A series of proposals were submitted, ranging from effective repeats of the "Richelieu" design with minor improvements (the Project A series) to plans that shifted the superfiring main battery turret aft of the superstructure (the Project B series), to the nine-gun variants that kept two triple turrets forward and a third aft (the Project C series). All three basic formats included several variations that incorporated changes to the composition and arrangement of the secondary and anti-aircraft batteries.