The Diaoyutai islands were not always such a hotbed of controversy, in fact, they were a sort of loophole.
After the Kuomintang authorities discovered Su Beng's involvement in a plan to assassinate Chiang Kai-shek, he fled from Taiwan to Japan. Taiwan was under strict martial law, so in order to get out of the country Su Beng stowed away, for several days, in a boat exporting bananas to Japan.
During the 40 years (from 1952-1993) that Su Beng was exiled in Japan, he managed to illegally enter Taiwan a few times via the Diaoyutai islands. How did he do it? With a bit of planning and the help of his underground "Taiwanese gangster" connections, he first traveled to Okinawa; making his way to the unclaimed Diaoyutai islands; there he got on a Taiwanese fishing boat going back to Taiwan. His earliest "trip" back to Taiwan was in 1967 and the last one, was in 1993.
Clearly, 40 years of exile in Japan didn't put a dent in his work for Taiwan's independence. In fact it was quite the contrary.
In those 40 years he was among the first to bring the authentic taste of Northern Chinese style fried noodles and dumplings to Japan. It was a huge success; in a just few years he went from running a humble food stall to purchasing a building which served as a noodle shop, personal residence and underground revolutionary training center. Activists from Taiwan were invited stay at the noodle shop where they were secretly trained by Su Beng. Su Beng had reestablished contact with underground activists in Taiwan, many of whom were probably associated with the Taiwan Independence Armed Corps. He had formed this group in 1950 after returning to Taiwan from China. The group stockpiled weapons and kept surveillance over Chiang Kai-shek; their ultimate goal was to assassinate Chiang Kai-shek. The noodle shop's earnings were funneled back into Taiwan to support the underground Taiwan independence movement.
Of course one of his greatest accomplishments during those 40 years of exile was the research and writing of Taiwan's 400 Years of History. Much of the research for the Japanese language version (which came first) was readily available in Japanese public libraries. But in order to get accurate facts, statistics and data for the Chinese language version, bribes were paid and documents were smuggled out of Taiwan to Japan. Even before Su Beng was able to publish the book, Kuomintang authorities tried to stop Su Beng by trying to buy the publishing rights from publishers of the book. Today Taiwan's 400 Years of History is still considered to be the one of most complete and accurate records of Taiwan's history and facts of its time.