Tani Bunchō (1763−1840) was a representative painter of the late Edo period who is said to have perfected Edo Nanga, a school of Japanese painting that flourished in this period. The subject of the painting, Ono Ranzan (1729−1810), was a leading specialist in the traditional pharmacognosy (study of medicines derived from natural sources) of the day. Ranzan asked Bunchō to paint the portrait just a year before his death. Bunchō first made a sketch of Ranzan’s right side, which Ranzan did not like, insisting that the bump on his left shoulder was a good luck charm that should be shown in his portrait. In response to Ranzan’s wish, Bunchō started over and depicted his subject from the left side. The portrait is a remarkable work that illustrates the undiminished spirit of Ranzan, who is known to have devoted himself to study even in the very last stage of his life.