How did they break the Japanese secret code in World War ll?

The Japanese 'Purple codes' were the most difficult to crack as arranged by colours of difficulty. Japanese diplomats in Germany used the Enigma cipher machines to transmit signals by radio Morse code to the Japanese high command. Huge efforts by Allied code breakers using the first optical reading of paper tape. Vacuum tube computers running new software algorithms performed multiple attempts to turn these codes into plain text. The codes were eventually broken by the US Army signals Intelligence corps and remained unknown to the Japanese.