French diplomat Léon Roches considered helping the shogunate stop the imperial advance, but Yoshinobu rejected the plan because he would not fight the emperor. That failure allowed Harry Parkes to secure a strict neutrality agreement among the foreign powers. On paper, the rule barred both sides from receiving outside military supplies. In practice, Britain could accept neutrality after Satsuma, Choshu, and Tosa had already accumulated British ships, weapons, and ammunition. French support to the shogunate had not reached a comparable level, so freezing new assistance preserved an existing imbalance rather than creating an even contest.
Notable Point · 1:55:24-1:57:01
Neutrality froze an already unequal supply position
A wartime neutrality agreement favored the imperial coalition because British-backed domains had already received ships and ammunition while French aid to the shogunate remained incomplete.