What was Takeshi Obata's first manga?

Obata was noticed early. As a schoolboy he re-read Shotaro Ishinomori's Cyborg 009 until it shaped his ambitions, and in 1985 his one-shot 500 Konen no Shinwa took a prize in the Tezuka Award. He joined the Weekly Shonen Jump staff and assisted artist Makoto Niwano before winning his own series.

That series was Cyborg Jii-chan G, which ran in Weekly Shonen Jump from issue 22 to issue 52 of 1989 and was collected in four volumes. It is credited to Shigeru Hijikata, a pen name Obata did not keep. The hero, Tokijiro Kaizo, is a 70-year-old genius scientist who retires to farming and converts himself into a 2,000-horsepower agricultural cyborg, to his family's horror. It is a gag manga, closer to a vintage comedy strip than to anything on the rest of this shelf.

It is also the exception that explains his whole career. Jii-chan G is the one series Obata both wrote and drew. Every series after it, from Arabian Lamp Lamp in 1991 onward, pairs him with a writer, and his fame rests entirely on the drawing half of the credit.