Titles: Mutsu no Kami, Mimasaka no Kami

Third-generation lord of Sendai-han, 19th head of the Date Clan, sixth son of Date Tadamune. His mother was the sister of the emperor's mother, making Tsunamune the emperor's cousin. He became the heir after the death of his elder brother, Date Mitsumune.

He was given to dissipation, which later lead to a rebellion to put his two-year-old eldest son, Date Tsunamura, in his position. However, there are theories that it was a pretense for the Shogunate, which was watching him closely. He was a person of refinement who left behind great works of art, poetry, calligraphy, laquer, and sword.

He died in Edo of cancer of the larynx, and was entombed in the Zenouden.