We would like to thank Daiichiro Sugimoto, Toshikazu Ebisuzaki, Makoto Taiji, Tomoyoshi Ito, Toshiyuki Fukushige and many others who were involved in the development of the six generations of GRAPE hardwares, and Yoko Funato, Simon Portegies Zwart, Steve McMillan, Piet Hut and again many others for discussions and collaborations in software development and scientific works on GRAPE hardwares. This work is supported by the Research for the Future Program of Japan Society for the Promotion of Science (JSPS-RFTP97P01102).