Final answer:
Medieval Japanese and European cultures both featured a strict societal hierarchy and a warrior class that adhered to a code of conduct, with the Bushido code in Japan and the chivalric code in Europe.
Step-by-step explanation:
A similarity between medieval Japanese culture and medieval European culture was the strict societal structure and class systems existing in both regions. In Japan, this was exemplified by the hierarchy which placed the emperor, court nobles, and shogun at the top, followed by the samurais, and then by peasants, craftsmen, and merchants. Likewise, medieval European society was organized into a feudal system with a king or lord at the top, followed by vassals and knights, and then peasants or serfs at the bottom.
Both cultures also valued codes that governed the behavior of their respective warrior classes; the samurai of Japan followed the Bushido code, emphasizing loyalty and sacrifice, while European knights were expected to abide by the chivalric code, which stressed honor and proper conduct.
Despite the differences in the specifics of their beliefs and practices, the emphasis on hierarchically structured societies with a distinct warrior class abiding by a strict ethical code presents a significant similarity.