While the issue on the diplomatic relations with Joseon Dynasty was stranded on a reef, Japan considered that the diplomatic relations with Qing which was a suzerain power of Korea should be concluded in priority to that, therefore, Sakimitsu YANAGIWARA and Yoshimoto HANABUSA were sent for the preliminary negotiations on July 27, 1870, followed by Date, a legitimate commander-in-chief, who led the negotiations to the final conclusions along with above mentioned Yanagiwara who had been appointed as a vice commander prior to it.
李氏朝鮮との国交問題が暗礁に乗り上げている中、朝鮮の宗主国である清との国交締結を優先にすべきとの考えから1870年7月27日（明治3年6月29日(旧暦)）柳原前光・花房義質を派遣して予備交渉を行い、次いで正規の大使として伊達が送られ、副使となった柳原とともに詰めの交渉を行った。