|the army of Takeda Shingen|
I think 'traditional' wargame units of 2 or 3 ranks would not be correct and not give the frontage required.
Fortunately, a clever fellow on the internet, who goes by the nom du net of Evalerio, has done an in depth study of things and has posted handy interpretations for us, complete with nice graphics:
|Takeda Army Deployment|
You can see his full break down of the command structure and organization on this forum.
He's also done a very detailed study of Samurai heraldry, and you can view some of his work on this other forum. Again complete with lovely graphics like this:
I can only hope Evalerio puts out a book on all this.
But from what I can sort out; it seems the mon, or badge of the Daimyo (great lord) is the unifying element. All ashigaru and lesser samurai would wear his mon. Different colours could be used to designate different divisions. Horizontal and diagonal stripes on the nobori and sashimono could be used to designate units within a division. Higher ranking samurai, commanding divisions under the daimyo, would be allowed to display their own device on their uma-jirushi.
Of course, I could be wrong. But it's a start.
I'll need more flags. A lot more flags.