1920年代前期受到四川內戰與紛亂的影響，日本在長江上游地區的商務與航運發展遭受嚴重威脅，輸船頻遭中國軍隊徵用或攻擊。然而長江上游特殊的地理環境與四川獨立於北京政府之外的客觀環境，卻使得日本傳統正規的使領交涉無法發揮應有的作用，海軍也無法像在長江中下游地區一樣提供充分支援。日本想要在此類徵用或攻擊事件上討回公道，並非易事。其次，川軍攻擊日本輸船初始並未帶有針對性或排日情緒，僅是企圖課徵非法稅收或強制徵用輸船。不過，日本輸船多次疑似涉入、介入四川內戰事務，引起部分川軍派系的敵意，間接導致重大中日衝突事件的發生。再加上領事與海軍系統對於中日衝突問題的看法也不太一致，使得此善後處理益形棘手。最後，自1922年、1923年開始，派駐在長江流域的日本第一遣外艦隊，為了因應日益嚴重的長江上游航行安全問題，逐漸探取積極的作為來強化保護日商航行安全。姑且不論海軍護航或動武方針是否真能達到提高航行安全的目的，強硬武裝政策所引起的後續效應，反倒可能為航行安全問題投下更不易處理的變數。長沙案、宜陽丸案、德陽丸案等一再發生的中日衝突事件，勢必再起漣漪，引起一波波群眾運動，諸如排斥與燒毀日貨、抵制日本輸船、反日示威遊行、對日商罷業等活動此起彼落。因此，海軍介入保護與避免排日運動之間，分寸應該如何拿捏，實考驗著日本駐華海軍與使領的智慧。

In the first half of 1920s, Japanese shipping and business on Upper Yangtze were greatly threatened by the civil wars and unrests in Szechuan. But, its geographical conditions and independence from the Peking government weakened the Japanese diplomats and consuls' regular negotiations, and refrained their Navy from taking operations. It was not an easy work for Japan to get what it wanted. Besides, The Szechuanese attacks on Japanese vessels were not brought up by the anti-Japanese sentiments but for practical purposes of illegal taxes and transportation. However, due to Japanese steamers' having got involved in the civil wars in Szechuan, some military factions began to resent the Japanese, resulting in serious Sino-Japanese conflicts. Finally, since 1922, the Japanese Navy has to take the hard line to deal with the navigation securities on Upper Yangtze. This strong military interference, regardless of the doubt as to its effectiveness on the improvement of this situation, whether it can improve the situation or not, must arouse more violent anti-Japanese movements, such as boycotts and demonstrations, that would surely make Upper Yangtze shipping issues more complex. The meditation between the Navy's interference and the avoidance of anti-Japanese campaigns by the Japanese diplomats, consuls and naval officers was a challenge to their determination and decision.