- Born: 1697, Edo
- Died: 1762, Fushimi
- Other Names: 渡辺洪貢 (Watanabe Kôgu)
- Japanese: 渡辺 善右衛門 (Watanabe Zen'emon)
Watanabe Zen'emon was a retainer to the Inaba family of Yodo domain, and the author of many notable records and other writings on a variety of subjects, including martial arts, military studies, ikebana, the history of Sakura City, elephants, and the 1748 Ryukyuan and Korean embassies to Edo.
Watanabe was born in 1697 in the Inaba mansion in Edo, and was raised in the castle-town of Sakura, where the Inaba were (briefly, at that time) lords of Sakura domain. As an adult, Watanabe inherited his own sub-fief or stipend of 150 koku. In 1723, the Inaba were transferred from Sakura to Yodo domain, based at Fushimi, and thus Watanabe moved as well.
In 1729/4, an elephant from Vietnam was brought before the Emperor; Watanabe's volume Zô kiyô (roughly, "Elephant Bulletin") records what he saw of, or heard about, this elephant's passage through the city. In 1748, Korean and Ryukyuan embassies separately passed through Fushimi and Kyoto on their way to pay respects to the shogun in Edo; Watanabe's Nyûrai Ryûkyû ki and Chôsenjin raihei ki record, again, what he either witnessed directly, or heard about, these events.
He died in Fushimi in 1762.
- Hirayama Toshijirô 平山敏治郎, "Nyûrai Ryûkyû ki" 入来琉球記, Minzoku gaku kenkyûsho kiyô 民俗学研究所紀要 3 (1978/12), 98-99.
- Several of Watanabe's writings about life in the castle-towns of Sakura and Yodo can be found in: Nihon shomin seikatsu shiryô shûsei 日本庶民生活史料集成, vol 10, Tokyo: San'ichi Shobô (1985).