The sixth son of Watanabe Kenmotsu Tadashi, a Tokugawa retainer based at Sunpu castle, he took on the name Toda when adopted by his uncle, Toda Masatsugu, following his father's death. Toda would later take on a variety of other names, including his birth name Hyô, adult names Yasumitsu and Moemon, and art-names Mosui and Rokanken.
Mosui's works included Murasaki no hitomoto, Wakaba, and Nashimoto-shû.
He died in 1706, and was buried at Sensô-ji.
- Plaques on-site at Mosui's grave, at Sensô-ji, Asakusa, Tokyo.