"中日密約"是巴黎和會山東問題中日爭執的焦點。和會前夕北京政府外交政策方針由"親日"轉向"親日聯美",陸征祥到達巴黎后經與北京政府商議,確立"聯美制日"方針。中日代表圍繞山東問題展開正面交鋒,中國決定將所有戰時密約交由和會裁判。日本堅持1915及1918年的中日條約有效,美國不承認所有戰時"中日密約",中國主張1915年中日"民四條約"不能作為日本取得德國山東權益的依據。中國代表團事先不知1918年"中日密約"詳情,在和會期間方逐步獲知密約全部內容。中國向和會要求將戰前德國在山東的權益直接歸還中國,日本則主張由其繼承這份權益后,再有條件轉交中國。隨著和會形勢變化,美日妥協,不談"中日密約"是否有效,決定讓日本繼承德國在山東的經濟權利,日本作出口頭聲明,從速將山東半島連同完全主權交還中國。中國拒簽對德和約后,代表團建議北京政府堅持不承認密約、由國際調停山東問題的立場,拒絕與日本開議。山東問題由此轉入新的處理渠道。

The"Sino-Japanese secret agreements"were a focus of disputes between China and Japan over the Shandong issue at the Paris Peace Conference.Before the Conference,the Beijing government’s foreign policy had shifted from being"pro-Japanese"to"pro-Japanese,allying with the US."But after Lu Zhengxiang(Lou Tseng-Tsiang)arrived in Paris,after conferring with the Beijing government,China’s policy direction changed to "allying with the US,checking Japan".The representatives of China and Japan engaged in a direct confrontation over the Shandong issue.China decided to submit all its wartime secret treaties to the Peace Conference for arbitration.Japan insisted that the Sino-Japanese treaties of 1915 and 1918 were valid,but the US did not recognize them.China urged that the Min Si Treaty of 1915 could not be used as the basis for Japan’s acquiring German rights and interests in Shandong.The Chinese delegation were originally unaware of the details of the Sino-Japanese secret treaty of 1918;they only learned its full contents during the Peace Conference.At the Conference,China demanded that Germany’s prewar rights and interests in Shandong be directly returned to China,but Japan proposed to take them over and pass them on to China under certain conditions.In accordance with the changing situation at the Peace Conference,the US and Japan reached a compromise.They avoided the question of whether the treaties were valid,and decided to let Japan take over Germany’s economic rights in Shandong.Japan made an oral statement to the effect that complete sovereignty over the Shandong Peninsula would be returned to China without delay.After China refused to sign the peace treaty with Germany,the Chinese delegation recommended that the Beijing government take a firm position on not recognizing the secret treaties,allowing international mediation over the Shandong issue,and refusing to negotiate with Japan.The resolution of the Shandong issue thus shifted to a new channel.