作为台湾的附属岛屿，钓鱼岛群岛在中国明清时行政隶属福建，与琉球本来不存在牵连。其原因在于，琉球与中国大陆之间有一条“黑水沟”（现在称“冲绳海槽”或“中琉海沟”），它最深处达2700多米，天然地将钓鱼岛与琉球分开。并且，这条海槽所形成的自然条件，使琉球或是日本方向过去钓鱼岛的船只逆风逆流。从而，受制于当时的航海条件，让琉球或日本在19世纪以前到达并“发现”钓鱼岛，在事实上难以实现。

1895年，因甲午战争失败，中国被迫割让整个台湾及其附属岛屿给日本，此后日本殖民主义统治台湾长达50年，直到1945年第二次世界大战结束。期间，钓鱼岛群岛作为台湾的一部分，亦被割让并转由日本殖民统治。作为偏远的无人小岛群，在被日本殖民统治的50年间，因对钓鱼岛的利用有限，日本是将钓鱼岛置于台湾还是琉球管辖，也并不确切。

中国是二战中的主要作战盟国，亦是最大的受害国，《开罗宣言》《波茨坦公告》以及1945年《日本投降书》均明确规定台湾应当返还中国。于是，中国当局在1945年10月正式接管台湾，钓鱼岛作为台湾的附属岛屿，其主权亦随同回归中国。

然而，在20世纪60年代末和70年代初钓鱼岛区域发现丰富的油气资源之前，整个钓鱼岛作为偏远小岛群，其实鲜为中日两国或国际社会关注。作者努力回溯，发现钓鱼岛争端之产生，在于二战后以下情况的发生，钓鱼岛“被”裹挟于琉球。经历了这些微妙的环节，钓鱼岛问题才逐步酿成争端:

1.1945年后的战时占领期间，琉球被以美国为首的盟军实行“分离性处理”，而钓鱼岛被绘入一些琉球的军事地图中；

2.1951年《旧金山和约》签订，中国没有参加和约会议，亦没有签署此和约，但该和约第3条之“北纬29度以南的琉球及大东群岛”区域的陈述被视作包括了钓鱼岛在内，并在1953年美国琉球民政府所发布的第27号令的经纬度列举中得到体现；

3.1971年美国与日本签订《关于琉球与大东群岛的协定》，其中再次将钓鱼岛所在地理坐标列入所谓“琉球与大东群岛”的“返还”区域。

所以，二战后，钓鱼岛先后因琉球的“分离性处理”、美国的“施政琉球”，再到美日“冲绳返还”，而被层层牵连，最后被日本单方面采取了“控制”措施。因此，钓鱼岛争端的事实演变与琉球问题密不可分。综观日本的主权立场，除战前的“无主地先占”理论外，它的核心观点即是以上与琉球相关的三大理由，撇开琉球，钓鱼岛并未与日本直接发生联系。

本书以“国际法上的琉球地位与钓鱼岛主权”作为题目，意在重点分析二战后琉球在国际法上的地位，质疑日本对琉球的主权依据，同时廓清日本、琉球和钓鱼岛主权三者间的关系。

全书共分五章。第一章归纳琉球问题与钓鱼岛争议焦点的关联，梳理已有研究状况并对研究思路和方法有所介绍；第二章归纳钓鱼岛与琉球的关系及由来，从钓鱼岛与琉球的历史沿革开始，概述其区别与联系；第三章为1945—1952年的琉球与钓鱼岛主权，从二战后盟国对日本领土的处理开始，指出琉球从日本脱离后地位未定，但钓鱼岛的主权已随同台湾回归中国；第四章为1952年以后的琉球地位问题，探讨《旧金山和约》签订后对琉球法律地位的影响，指出“剩余主权”论的法律障碍，进一步分析《琉球与大东群岛协定》的非法性，提出日本对琉球缺乏主权依据、琉球人民应该享有自决权等问题；第五章对日本在钓鱼岛上的论据进行专门分析，指出其以对琉球的主权为基础的钓鱼岛主张不过是“空中楼阁”。同时，从国际法角度，作者对“中国放弃/默认”论、日本“有效控制”论是否成立也进行了探讨。

本书旨在丰富对钓鱼岛问题的客观研究，而不是直接致力于解决钓鱼岛争端。其创新性可以体现在三个方面:一是对琉球的法律地位这个被视作“悬案”的难点问题进行法律的定性分析。二是弥补国内学界在钓鱼岛主权研究上国际法专论之欠缺。三是综合历史与实在法的方法进行分析论证。在历史方面，本书引用的部分地图、历史文件由作者亲自查证收集，并且，对于一些较重要的国际文件的英文原文，作者都尽量放入引注或附于文后，以供参考方便；实在法分析方面，本书较严格地遵从体现国家同意的条约国际法与习惯国际法规则，注意对规范性文件的国际法效力进行区分、识别和探讨。

Abstract

Diaoyu islands were under the administration of Fujian Province（affiliated with the Taiwan prefecture）in the Qing and Ming Dynasty of China，and had no relevance in deed to the Ryukyus during a long history，because there was an accepted customary boundary named the“Black Water Trench”，Okinawa Trough or ZhongLiu Trough today，dividing the Diaoyu Islands clearly from the Ryukyus.The trough is even more than 2700 meters deep in some areas.Also，the geographic surroundings show that，sailings from the Ryukyus or Japan to Diaoyu islands are against the winds and flows，so it was almost impossible for the Ryukyus or Japanese natives from their lands getting to“discover”Diaoyu islands before the 19th century.

In 1895，China was forced to cede Taiwan and all the affiliated islands thereto to Japan as the consequence of the defeat in Sino-Japanese War.From then on，the whole Taiwan（including Diaoyu islands）was under the Japanese colonization for 50 years.Actually，for the islands are remote and desolate，it seemed doubtful that Diaoyu islands had been designated by Japan as part of Taiwan prefecture or Ryukyu prefecture during the 50-year-long colonization.In 1945，following the end of the Second World War，Taiwan was returned to China.Chinese authority officially took over the governance of Taiwan in the October of 1945 in accordance with the Cairo Declaration，Potsdam Proclamation，and Japanese Instrument of Surrender.Hence，as part of Taiwan，the sovereignty of Diaoyu Islands reverted to China as well.

However，these remote and isolate islands had been little noticed by both China and Japan，or the whole international society，until the optimistic prediction of gas and oil deposits in that region were explored and reported by the media in about the late 1960s or the beginning of 1970s.Therefore，looking back carefully，how the Diaoyu islands dispute originated? In the strict sense，the following points concerning the post-war subtly settlement of Ryukyus（Diaoyu islands involved）should be noted:

（1）After the WWII，the Ryukyus had been detached from the Japanese territory and occupied straightway by the military government of allied powers（the U.S.as a major ally）since 1945.Some military maps recorded the Diaoyu islands as part of Ryukyu islands；

（2）In 1951，the Article 3 of San Francisco Peace Treaty with Japan indicates that Diaoyu Islands are included in“Nansei Shoto south of 29deg.North latitude”（Ryukyu or Ryukyus is the abbreviation of Nansei shoto as well），although Chinese government neither attended the San Francisco conference nor signed that Peace Treaty.Again，the No.27 Act in 1953 issued by the United State Civil Administration of Ryukyus showed the same content；

（3）In 1971，the US and Japan signed the Agreement on the Ryukyu Islands and the Daito Islands，and the geographic coordinates of Diaoyu Islands were included again by the so-called reversion area of the Ryukyu Islands and the Daito Islands.

Therefore，in the light of a series of post-war vague arrangements like the“detachment settlement”of Ryukyus，the U.S.“administration”of Ryukyus，and the“reversion of Okinawa”，the Diaoyu islands became subtly linked with the Ryukyus bringing about the current situation of Japanese“control”.It is apparent that almost all the Japanese claims on the Diaoyu islands are based on her titles to the Ryukyus（the three points listed above are the bases of the Japan’sovereignty arguments）.Hence，the clarification of the legal status of Ryukyus shouldn't be absent while analyzing the sovereign issues of Diaoyu islands.

The topic of this book is Territorial Status of the Ryukyus and the Sovereignty of Diaoyu Islands in International Law.It purports to doubt the legal grounds of Japan's claims over the Diaoyu islands through questioning the legal status of the Ryukyus，and to clarify the relationships among the Ryukyus，Japan and the Diaoyu islands from the international law perspective as well.

There are five chapters in the book.Chapter one focuses on the connection points between the Ryukyus issue and the Diaoyu islands dispute，summarizing the previous researches and introducing the methodology of this study.Chapter two is to overview the historical differences and relationships between the Diaoyu Islands and Ryukyus，discussing the origins of the Diaoyu islands and Ryukyus issues.Chapter three is to analyze the territory status of the Ryukyus and the sovereign situation of Diaoyu Islands during the period of 1945—1952.The issue of Diaoyu islands involved in some military maps was intensively discussed in this chapter，along with the investigation of the Ryukyus’status based on the relevant postwar documents like Directives，Orders and other Acts issues by the Allied Powers.Chapter four aims to explore the status of Ryukyus after the sign of San Francisco Peace Treaty.This chapter highlights the following issues: the invalidity of the“residual sovereignty”，the illegitimacy of Agreement on the Ryukyu Islands and the Daito Islands and so on.Chapter five specializes in Japan's comprehensive claims and the conclusions include: Japan doesn't have any legal titles to the Ryukyus；Japan's claims over the Diaoyu islands which based on the Ryukyus are weak and fake，the Ryukyus have a status of her own，including the realization of the right of self-determination；Japan's arguments like the so-called“Chinese abandonment of the territory”，“Japanese effective control”，etc.，are all without legal bases.

This study isn't designed to resolve the dispute but enrich the existing researches on the Diaoyu islands via taking a specific Ryukyus' approach.The innovations of this book can be manifested in three aspects: First，it partly resolved the“conundrum”of Ryukyus’legal status，which seemed had perplexed the academic circle for a long time.Second，it fills in the blanks of the monographs specializing in the sovereignty of the Diaoyu islands in Chinese international law field.Finally，the approaches of this work connected history to law.Regarding the historical approaches，parts of the maps and historical documents cited are personally collected by the author.Also，for the convenience of further researches，some significant documents in English are laid in the footnotes or appendices.With respect to the legal approaches，this book strictly subjects to the positive international law perspective，identifying the legal norms and sources in accordance with the criteria of treaties and customaries emanating from states' own free will.