An analysis of Mushashi (greatest swordsman in Japanese history) caught my eye:

He lived in a land obsessed by status and tradition, however, he appeared to ignore both. Usually duels observed ceremony and ritual, but Musashi only cared about the practical nature of fighting and strategy. His unkempt appearance only added to this.

That sounds remarkably like the many stories about General Grant, whose distaste for American obsessions with patronage and appearances was famously captured the day he casually accepted unconditional surrender from Robert “shiny shoes” Lee.

Grant… hunches over (the correct) small table in the shadowy background, his muddy boots offering another point of contrast to Lee’s polished footwear.

Lee infamously fought primarily for his family dynasty, putting loyalty to their slavery empire above state (Virginia) and certainly far above loyalty to Constitution or country (discarding his American citizenship and never regaining it).

His “shiny shoes” reputation (as depicted in the many images of his surrender) reflects his cushioned elitist life, devoid of hardship — a love of monarchy with violent aspiration to leave “unpleasant” realities to only servants and slaves.

Grant cared only about the practical nature of fighting and strategy, thus had an unkempt appearance. His boots were dusty as he had famously spent the day riding hard, checking on the welfare and needs of his soldiers.