The 8.4–9.0 Mw Sanriku earthquake strikes the area around Sendai in northern Honshu, Japan. Inundation from the tsunami extended several kilometers inland.

The 869 Jōgan earthquake and its associated tsunami struck the area around Sendai in the northern part of Honshu on 9 July 869. The earthquake had an estimated magnitude of at least 8.6 on the moment magnitude scale, but may have been as high as 9.0, similar to the 2011 Tōhoku earthquake and tsunami. The tsunami caused widespread flooding of the Sendai plain. In 2001, researchers identified sand deposits in a trench more than 4.5 kilometres (2.8 mi) from the coast as coming from this tsunami.

Sendai is the capital city of Miyagi Prefecture and the largest city in the Tōhoku region. As of 1 August 2023, the city had a population of 1,098,335 in 539,698 households, making it the twelfth most populated city in Japan.

Honshu , historically known as Akitsushima , is the largest of the four main islands of Japan. It lies between the Pacific Ocean (east) and the Sea of Japan (west). It is the seventh-largest island in the world, and the second-most populous after the Indonesian island of Java.