Sodaisho (a commander in chief) (総大将)
Sodaisho was a commander in chief who lead an army composed of more than one corps. In particular, the term "Sodaisho" was often used to differentiate the highest ranking official from other generals in an army composed of more than one corps. Sodaisho were also referred to as Sotaisho, Shusho or Sosui.
Summary
Sodaisho is a concept used to refer to a busho (military commander) who lead an entire army within the battle history from the Heian to the Sengoku Period (period of warring states).
In a situation where troops were organized by a single samurai group, the leader of the samurai clan served as Sodaisho, or in many other cases, a Sodaisho would be selected from high-ranking warriors of a clan such as the Karo (chief retainer) and they held great authority in battles. On the other hand, in the case of troops being organized by allied samurai groups, each group had an independent chain of command and the Sodaisho was just a figurehead with relatively weak authority.
In either case, however, the position of Sodaisho standing at the top of the entire army was extremely appealing, so when the post was not performed by the Daimyo (Japanese territorial lord), the lord's family members and retainers competed for the position.
As it become the Sengoku Period, when daimyo established the commanding positions and classes in their military organizations such as the Samurai daisho (commander of warriors) or Ashigaru taisho (general in command of a troop of food soldiers), the military commander in charge of these positions was referred to as a Sodaisho.