You probably know the story of the codebreakers of Bletchley, whose top secret work to decipher the Enigma system the Germans used to encrypt their wartime communications did so much to help the Allies win the war, and which also laid the foundations for modern computing. Bletchley Park, the country estate where they worked, is open to the public and has been given a major upgrade, so I joined some Twitter friends for a look.

The train from Euston to Bletchley takes fifty minutes, and the entrance to Bletchley Park is opposite the station. There’s a display in the first building that explains the process from interception of the messages at listening stations around the country through their delivery to Bletchley by motor bike despatch riders to decoding and translation. We hear a lot (quite rightly) about the achievements of Alan Turing and the team of codebreakers at Bletchley, but less about the equally necessary work of the translators, especially those translating from Japanese, who had often only just learned the language themselves. Some of their study aids will look all too familiar to anyone who has been through the process themselves.

Japan had been one of the most important targets for the Government Code and Cipher School (the precursor to Bletchley) in the pre-war period, but its entry into the war following the attack on Pearl Harbour in 1941 brought it to the fore again. Following the end of the war against Italy in 1943 the Japanese operation at Bletchley was expanded and moved from Hut 7 to Block F, which became know as the Burma Road because of its length and number of subsections. The blocks were more substantial buildings that looked out over the lake.

The Japanese had their own system of morse code, based on a combination of kana (the phonetic Japanese alphabet) and romaji, a system for transliterating kana into roman lettering. They used super-enciphered codes, where a random string of figures was added to the figures in the encoded message.

German communications were encrypted using the Enigma machine. A version was developed for German-Japanese communications called the Tirpitz. This worked in the same way as the Enigma machine, by generating random letters when a key was pressed.

Breaking the Japanese super-enciphered codes, which was already done in 1939, was not the main challenge. The difficulty was translating them, given the shortage of Japanese speakers. At first SOAS ran courses, but at two years duration they were too long for Bletchley’s purposes. So a retired Naval officer called Tuck, who had been teaching Japanese for forty years, began to give six-month courses, called the Bedford School. It worked by bombarding students with a very limited vocabulary on phonograph records. The Director said, ‘after the fifth week they’re either carried away screaming or they’re nipponified.’

Nearly all the original huts where the codebreakers worked are still at Bletchley, with two of them restored to show what it was like working in them under intense pressure during the war.

The main house has been beautifully restored, with some rooms reconstructed as they would have been at the height of Bletchley’s activities.

All in all, a fascinating day out. If you feel like a trip, Bletchley is open daily 9:30 am to 5 pm in the summer, and until 4 pm in the winter. Entry for adults is £15 but there’s currently a two-for-one offer if you go by train.