I had just recently played a one on one and the scenario went like this:
I had advanced the hill and surrounded his forces. My militia riflemen set on a tall hill to his left flank and his archers were set to defend with some spear men. Then he fired upon my Samurai and I advance with them to lure the spear men into the range of fire and push back the archer's range. But the spearmen route and the other militia units follow suit... then the whole army starts routing!