Found this:
As recently as 1953, according to research done by Ampotan, the PRC considered the Senkaku Islands to be Japanese territory, as they were claimed in 1895 through the legal caveat of terra nullius. That the PRC only claims them now is, in fact, due to territorial and resource ambition. To sum up Ampotan's findings in his excellently sourced, cited and researched article:
on the history of the islands:
"
The first recorded mention of the islets was in 1534 in Chen Kan’s Records of the Imperial Mission to Ryukyu. Chen, an envoy of the Ming Dynasty emperor to the Ryukyus, described his trip from China to Naha, as well as the customs of the native Okinawans. In his and several other accounts over the next two centuries, the islets were mentioned merely as geographic landmarks.
The Chinese never indicated they considered them their territory, or anything more than specks in the ocean.
The first Japanese mention is in the Chuzan Seikan (Mirror of Chuzan), i.e., records of the Ryukyu Dynasty, which dates from 1650. As in the Chinese records, there is no indication they were considered anyone’s territory.
Fukuoka native Koga Tatsuhiro was making a living in Naha, Okinawa, catching and exporting finfish and shellfish when he discovered in 1884 that the islets were the habitat of the rare short-tailed albatross. He started collecting albatross feathers for sale in addition conducting to his fishing business. Ten years later, he applied to the government of Okinawa Prefecture to lease the islands. They turned him down because they weren’t sure who the islands belonged to. Koga then applied to the interior and agriculture ministries in Tokyo, and they turned him down for the same reason.
That did bring the islets to the attention of the Japanese government, however, and Koga’s persistence paid off. The Japanese claimed the islands under the legal principle of terra nullius—any nation can claim as its own, territory that is unclaimed by any other nation—and it became part of Japan.
The Senkakus were uninhabited and unclaimed—indeed, they had never been administered at any time by the Chinese government, and there is no record of any Chinese ever living or working there.
The Chinese later charged the Japanese swiped the islets at the same time they wound up with the booty of Taiwan and the Penghu Islands at the end of the 1894-1895 Sino-Japanese War."
furthermore, according to Ampotan's research, the islands fell under US control after the end of WWII, and were returned to Japan with the return of Okinawa in 1971.
a timeline after the war goes like this with regards to PRC claims (and lack thereof) after WWII:
8 January 1953: Renmin Ribao (People’s Daily) published an article titled “The Ryukyu Islanders’ Struggle against American Occupation” (i.e., Okinawa). The article mentioned the Senkakus, used that name, and stated they were part of the Ryukyus. Here’s a post from Michael Turton’s fine blog, The View from Taiwan, with more more detail on the article.
November 1958: A Beijing company published a map of the world showing the Senkakus as Japanese territory and using the Japanese name.
October 1965: The Research Institute for Taiwan’s Ministry of National Defense published a series of world maps. It showed the islets as part of Japanese territory and used the Japanese name Senkakus. Here is a color reproduction of the map itself on a Taiwanese website. The poster worries about how the map would affect the Taiwanese claim. Scroll down to see the magical mystery change on the map for the 1972 edition.
6 October 1968: The Taiwanese newspaper Lianhebao (United Daily News) published an article explaining that Taiwanese fishermen were prohibited from fishing in the Senkakus. They used the Japanese name.
12 October – 29 November 1968: Maritime specialists from Taiwan and South Korea conducted sea floor surveys of the East China Sea with the cooperation of the Economic Commission for Asia and the Far East (ECAFE), the regional arm of the United Nations Secretariat for the Asian and Pacific region. The report stated there was a possibility of large quantities of oil and natural gas under the seabed. It was later confirmed that there are at least 92 million bbl of oil available, with estimates of up to 100 billion bbl of oil, roughly equivalent to the 112.4 billion bbl of Iraq.
May 1969: The government of Taiwan provided oil exploration rights to Gulf, planted the Taiwanese flag on the Senkakus, and notified the world’s wire services of its action.
January 1970: The Taiwan government published a geography textbook for junior high school students that called the islands the Senkakus and treated them as Japanese territory
September 1970: The Okinawan police sent a ship to the Senkakus, removed the Taiwanese flag, and gave it to the Americans.
11 June 1971: The Taiwanese government claimed the islands as their own territory for the first time. Less than one week later:
17 June 1971: The treaty returning Okinawa to Japan from American control was signed.
30 December 1971: The People’s Republic of China claimed the islands as their own territory for the first time.
In 1992, China adopted legislation that authorized the use of force to enforce Chinese claims to the islets.
as such, Ampotan concludes, judging by the behavior of the PRC with regards to the arrest of Zhang Qixiong in 2010–the use of threats, threats of force, and overall immature behavior unfitting for a modern nation (including the decision to create "battle capable fishery vessels"), as posed against the far more measured response of Japan, Ampotan concludes that what China is performing is not merely a resource grab, but rather:
"…how a nation with arrested political development and without a sense of morality, with neither real friends nor real ideals–only size, money, and the desire to recreate the world as it existed two millenia ago–tries to seize the territory of another nation in the modern age and create a contemporary suzerainty."
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I believe the Japanese really owned the Senkakus. I'll bet the Chinese would not agree to international arbitration.The Chinese are the REAL professional land grabbers of Asia.