Relatively speaking, feudal society in Japan was fairly liberal in terms of how women were perceived and what rights they were entitled to. More often than not, they could inherit estates, manage businesses (de jure) and voice their opinion about social affairs without borrowing a man’s throat or needing his permission.
During the Kamakura and Heian Period, it could be argued that these were the ‘most favorable’ of times for female warriors to come along and get ahead in their respective armies.
Much of warring was still very formal and ritualized.
Skirmishes occurred between small numbers of professional warriors but the skirmishing itself adhered to a huge number of ritualistic rules and stringent traditions. Fighters from the one side would name a specific individual opponent and demand they come forward to face them.
This was utterly different from the brutal and drastic clashes that delineated the total war of the Sengoku Era, when armies were a mix of draftees, professional fighters, and Samurai. The Sengoku era is where you could see thousands of bodies and corpses pressing against each other in the chaos of the battleground.