I am watching "Gunshi Kanbei", and Toyotomi Hideyoshi has just cut off his topknot in front of the lords of Setsu on his march to punish Akechi Mitsuhide for killing Oda Nobunaga. Why is this so significant for the assembled lords to be so impressed with this act?
It meant he was downgrading his own status. Possibly to prove that his army was there purely to capture Akechi, not to invade or mess with the local lords, though I'm speculating because I haven't watched this series and have never heard of the lords of Setsu before.