Which Shinkansen line was the first to open north of Tokyo?

The Tohoku Shinkansen was the first Shinkansen line to open north of Tokyo.

Its first section, between Omiya and Morioka, opened in 1982. Because the Tokyo terminal was not ready at the time, passengers initially connected through conventional rail from Tokyo to Omiya. The line was later extended south to Tokyo and north through the Tohoku region, serving cities such as Sendai and Morioka.

The Tohoku Shinkansen is often mentioned together with the Joetsu Shinkansen, which also opened in 1982. Joetsu serves Niigata and the Sea of Japan side, while Tohoku heads toward northeastern Honshu. The Hokkaido Shinkansen is a later extension beyond the Seikan Tunnel to Hokkaido, so it was not the first northern Shinkansen line.