Tashiro learned French and even became an assistant tutor of French at the age of sixteen. He studied botany both in Kagoshima and Tokyo and worked in the Ministry of Agriculture and Commerce between 1875 and 1879.  Returning back to his homeland, Kagoshima prefecture, he worked for the Department of Promoting Industry in the Prefectural government.

Then, he took the first opportunity to visit Okinawa prefecture in 1882. He was asked by the Ministry of Agriculture and Commerce to test the plant cinchona there. Besides carrying out his task, he travelled to the Miyako and Yaeyama Archipelagoes. was surprised to see the potential of Yaeyama, and wrote “A Proposal after a Trip to the Islands of the Edge in Okinawa Prefecture (Okinawa Kenka Sakishima Kairan Ikensho 沖縄県下先島廻覧意見書)” in 1882. He had studied tropical botany and the tropical industry of European colonies in his youth. So, when he saw the tropical vegetation in Ishigaki and Iriomote Islands, it seemed that he immediately hit on the idea that the Japanese would also be able to develop a tropical industry on the new frontier.

In the proposal, Tashiro suggested planting tropical vegetation such as cotton, sugarcane and tobacco.  In addition, he suggested developing fishery and coal mining in Iriomote Island where a coal bed had been found, but had not yet been exploited (Tashiro 1882). Tashiro approached government officials with his ideas, but none of them showed much interest (Nagayama 1930, 40; Tashiro 1893).