Source I

The Lytton Report (4 September 1932).

Without declaration of war, a large area of what was indisputably Chinese territory has been forcibly seized and occupied by the armed forces of Japan and has, in consequence of this operation, been separated from and declared independent of the rest of China. The steps by which this was accomplished are claimed by Japan to have been consistent with the obligations of the Covenant of the League of Nations, the Kellogg–Briand Pact and the Nine-Power Treaty of Washington, all of which were designed to prevent action of this kind … The justification has been that all the military operations have been legitimate acts of self-defence, the right of which is implicit in all the multilateral treaties mentioned above, and was not taken away by any of the resolutions of the Council of the League. Further, the administration which has been substituted for that of China in Manchuria is justified on the grounds that its establishment was the act of the local population, who spontaneously asserted their independence, severed all connection with China and established their own government. Such a genuine independence movement, it is claimed, is not prohibited by any international treaty or by any of the resolutions of the Council of the League of Nations.

[Source: The Lytton Report (4 September 1932). Copyright United Nations Archives at Geneva.]

Source K

Ryōichi Tobe, a professor of the history of modern Japan, writing in the chapter “The Manchurian Incident to the Second Sino–Japanese War” in the Japan–China Joint History Research Report (2011).

The Guangdong [Kwantung] Army continued its advance into Chinese territory … To serve as head of the new state, the Japanese took the deposed Chinese emperor Puyi out of Tianjin under cover of riots that the Japanese staged in the city and brought him to Manchuria. Japan’s position that it acted in self-defence to protect its own interests thus began to lose credibility, and the League of Nations grew increasingly suspicious. On October 24 [1931], the League Council voted for the withdrawal of Japanese troops by a specific deadline, but Japan’s opposition alone defeated the resolution. Finally, with Japan’s agreement, the League Council decided on December 10 to send a commission to the scene to investigate, and deferred any decision until the investigation was completed … the [resulting] Lytton Report refused to recognize the Guangdong Army’s actions following the Manchurian Incident as legitimate self-defence, nor did it accept the claim that Manchukuo had been born from a spontaneous independence movement.

[Source: adapted from Japan-China Joint History Research Report March 2011: The Manchurian Incident
to the Second Sino-Japanese War, by Tobe Ryōichi. Ministry of Foreign Affairs Japan,
http://www.mofa.go.jp/region/asia-paci/china/pdfs/jcjhrr_mch_en1.pdf.]