would overflow+ levy + retrain +raise army +retrain cause a development along the lines of military towns/cities?
The Chinese used border towns that housed soldiers who farmed the area in peace in addition to training, and could be called up for war.
The caliphates had cities that housed soldiers who acted as craftsmen, Merchants and landholders as hired hands/slaves worked the land, freeing time for training, and could be called upon for war or raids.
The benefit of such, besides the availability of soldiers, was that the army became self sustaining and economically productive, and it allowed the establishment of cities in conquered territory very rapidly, since the soldiers themselves had all the varied skills and expertise needed to establish a functional city.
Or do Ymar have a similar concept already? If so, how developed is it?