I think this refers to....
Shortly after the beginning of the Second Sino-Japanese War in July 1937, Izumo was attacked on 14 August 1937 in a series of raids by Chinese Air Force aircraft during the Battle of Shanghai. Most of the bombs landed in the river without effect, but two bombs landed among spectators, killing hundreds.[42] Izumo's Nakajima E4N floatplane and another from the light cruiser Sendai managed to get into the air and they claimed to have shot down one Curtiss Hawk biplane fighter and a Northrop Gamma bomber. Two days later, her E4N claimed to have shot down another Hawk.[12][43] Izumo was attacked that same day by a Chinese torpedo boat, but the torpedoes missed and the boat was abandoned by its crew.