He was companion in arms to his stepuncle Minamoto no Yorimitsu (944–1021), son of Mitsunaka; and is famous for his military exploits in a number of tales and legends.
Dominating Settsu Province as a focal area of maritime transportation in medieval Japan, the Watanabe family spread its influence widely.
The priest Mongaku Shōnin who urged Minamoto no Yoritomo (1147–1199) to start a war against the Taira, and who managed to get a letter from the Emperor Go-Shirakawa (1127–1192) to Yoritomo, requesting that he set up an army and liberate the country from the tyranny of the Taira, which enabled the Minamoto clan to take up arms,[2] was the son of Watanabe no Endo Mochito.
At the Battle of Dan-no-ura (April 1185), when the Dowager Empress Kenrei-mon-In, daughter of Taira no Kiyomori, tried to drown herself, she was pulled out by the samurai Watanabe no Mutsuru.
After the Genpei war, the Matsuura Watanabe received the additional titles of Gokenin (Direct Retainer of the Shogunate), and of Jitō (Military Governor).
The Kamachi were direct descendants of Minamoto no Noboru (848-918), like their cousins of the Watanabe clan, and had the titles of Shokan (Governing officer) of Kanzaki no shō estate (Hizen province), of Gokenin, of Jitō (Military Governor) of the County of Mizuma (Chikugo province),[4] and held the court rank of Kizoku (Officer).
Minamoto no Hisanao, son of Watanabe Hisashi, was 'Uhyoe no jo' (Officer of the guards of the Middle Palace), and owner of Mikuriya no shō estate.
In 1235, the Watanabe clan received from the Kamakura shogunate the responsibility of overseeing large shipments of tax and tributes due the shogunate from the provinces of western and central Japan[5] During the period of the Northern and Southern Courts (1336-1392), the Matsuura Watanabe sided with the Northern Court, and fought at the Battle of Chikugogawa (1359).
The Hakata Watanabe branch, were Daimyō (Grand feudal Lords) of Hakata Domain (Izumi Province) until the Meiji Restoration (1868), had a revenue of 13,500 koku, and descend from Watanabe Yoshitsuna (1611-1668), who was appointed Sobayonin (Grand Chamberlain) by Tokugawa Ietsuna (1651–1680), the 4th Tokugawa Shogun, and was the grandson of Moritsuna.
Even by the standards of Japanese names, there is an unusual degree of variation in the second kanji used to write Watanabe, with at least 51 recorded variants including the common 渡部, 渡邉 and 渡邊.
A basic translation of the name of the original village 渡辺 is ‘to cross over a river’, and sometimes people mistakenly write that the Watanabe are 'river crossers' which is incorrect.