Top text reads 凱旋記念 "commemorating triumphant return" 

Bottom text  is very faded but reads 上海事変 "Shanghai Incident" This is referring to the 1937 battle of Shanghai fought from August 13, 1937 to November 26, 1937. More than a million soldiers fought in this battle. This was the largest battle in the Second Sino-Japanese War and the largest urban battle in the history of earth at that point.