- Death: 1615
- Title: Iwami no Kami
Masanari was the eldest son of Hattori Hanzo. He served as the captain of the Edo Castle guards but became involved in a scandal. He was killed in the Osaka Summer Campaign (1615), possibly as the result of a bid to exonerate his damaged reputation, and was succeeded by his younger brother Hattori Masashige.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005