- Born: 1843/9/16
- Died: 1917/1/13
- Other Names: 長野桂次郎 (Nagano Keijirou); 米田 (Yoneda); 小花和為八 (Obanawa Tamehachi; childhood name); Tommy (nickname)
- Japanese: 立石斧次郎 (Tateishi Onojirou)
Tateishi Onojirô was, at the age of 17 or 18, the youngest member of the first Japanese Embassy to the United States. He joined the mission as an interpreter-in-training accompanying his adoptive father, formal interpreter Tateishi Tokujûrô. Likely due in large part to his youth and attractive appearance, Onojirô, known in the US as "Tommy" after his childhood name Tamehachi, became a favorite of the US media. He was often mistakenly referred to in the American newspapers as "Jateishi Osojero" or by various other misspellings of his name.
Following the Meiji Restoration, he took the name Nagano Keijirô. He served as a member of the Iwakura Mission, and later as an official overseeing immigration to Hawaii, and as an interpreter for the Osaka Appellate Court.