Haguregumo

Both are homages to famous liberal and progressive samurai Ryōma Sakamoto, a political activist during the late Meiji Period. In both anime, a fictional relation between Sakamoto and a young boy whom he mentors is shown. In Ryo, this is the full plot, in Haguregumo it is just one arc of a character in a more complex story. Ryo is far more serious and historical, while Haguregumo feels more like a nod from an admirer without intended historical accuracy. However, both anime show the assassination of Sakamoto in a Kyoto pub in detail. 

Both shows combine history with samurai slice of life. Both are set at the end of the Edo (Tokugawa Shoganate) era, 1860s.. The series depict family life with his wife, parents, and kids. Both shows feature real world samurai Ryoma Sakamoto and give homage to his ideas. Both have main characters notorious for womanizing.