In studying Japanese literature and the history of relations between Japan and Taiwan, Kuo has found that earlier generations of Japanese historians seem to have deliberately remained silent about the Japanese government's opium policy in Taiwan, nor do they make any mention of an incident in which the Japanese police massacred Taiwanese citizens in Tokyo.
郭譽孚說，他在深入探索日本文學和日本對台灣史的研究之後發現，在日本的台灣先民史料中，似乎刻意遺漏了日本在台灣的鴉片政策和日警在東京殘殺台灣人等史實。