This study examines the formation of the narrative of 'Hatta Yoichi' in the post WWII period. Hatta Yoichi, a Japanese engineer who undertook the development project of Kanantaishu and built the biggest dam in Asia during the Japanese Colonial period of Taiwan, has been introduced as "Japanese who loved Taiwan" and as a symbol of Japan-Taiwan friendship. In this study I analyze the transcripts of the interviews I conducted with the Chia-Nan Irrigation Association, Hatta Gishi Fusai wo Shitai-Taiwan to Yuko no Kai (the Association of honoring Mr. and Mrs Hatta and having friendship with Taiwan) and presidents of Taiwan, Ma Ying-jiu, Chen Shui-bian and Lee Teng-hui from 2007 to 2009. I reveal that the discourse of 'Hatta Yoichi' has been formed and transformed under the impact of the politics of Japan-Taiwan relationship.