"I'll bet it'd mean somethin if it had that risin sun on the collar and they was comin down Second Street about ten abreast"
War Flag of the Imperial Japanese Army (1870-1945)
Creative Commons AttributionWar Flag of the Imperial Japanese Army (1870-1945) - Credit: Vibracobra23

A reference to the insignia of the Imperial Japanese Army, as well as to Japan as the 'Land of the Rising Sun'.

Following the Japanese attack on Pearl Harbor, anti-Japanese sentiment ran high in America, aided in no small part by government propaganda. In terms of crude racial stereotyping much of this propaganda was not so far removed from the anti-Semitic images emanating from Nazi Germany.

The embedded video contains a clip from a 1943 Batman feature entitled Slaves of the Rising Sun, demonstrating how deeply anti-Japanese sentiment had infiltrated American popular culture throughout the war years.

 

World War II US Army poster
Public DomainWorld War II US Army poster - Credit: US Federal Government
US propaganda poster, encouraging Americans to avoid waste as part of the war effort. The caricature may be based on Hideki Tōjō
Public DomainUS propaganda poster, encouraging Americans to avoid waste as part of the war effort - Credit: US Federal Government