Japanese army and diplomatic codes. This article is on Japanese army and diplomatic ciphers and codes used up to and during World War II, to supplement the article on Japanese naval codes. The diplomatic codes were significant militarily, particularly those from diplomats in Germany.
Japanese army (IJA) and diplomatic codes were studied at Arlington Hall (US), Bletchley Park (UK), Central Bureau or CBB (Australian, US; in Melbourne, then Brisbane), the FECB (British Far East Combined Bureau) at Hong Kong, Singapore, Kilindi then Colombo and the British Wireless Experimental Centre in Delhi.