encodements into Shark and Dolphin during April. This policy paid good dividends; 12 pairs were broken in March and a number of reencodements obtained during April. In May new Turtle keys were used and most days were broken but after this work was once again given up; a few days were broken in June, July, and August until in August the key was finally abandoned. After October 11th traffic died completely.
In April also Trumpeter was first broken. Trumpeter was a High Command key, its content largely administrative, used mostly in the S. European area. At this time it used throw-on indicators and it was thought probable that we should break it regularly. When 2 pairs had been broken, its content was voted to be of little interest and no more was done until October when a series of reencodements appeared in Bloater. Trumpeter was at this time still a 3 wheel key but had ceased to throw-on; 2 more days were broken and once more work was given up. In April 1945 Trumpeter, now a 4 wheel key, reappeared in Holland and was thought likely to be the key on which the "Southern Redoubt" would communicate with the Germans continuing the fight in Norway. Once more a day was broken and the result was as disillusioning as usual. The war ended without Trumpeter having a chance to establish itself in the role it was said to be going to fill.
Another key began in April which was to have a much more interesting history - Bonito. It began in a small way. The traffic arrived, like Seahorse before it, from Twinn's Section with the suggestion that it might be Naval Enigma. Like Seahorse, Bonito was a 4 wheel key, using 5 letter groups and a throw-on indicating system. Other curious characteristics were the use at first of variable call signs and a change of key at midnight instead of midday; this latter habit disappeared on September 9th.
Bonito was at first the key used for traffic concerning experimental work on midget submarines in N. Italy but became later the operational key of the so-called Small Battle Units - Midget Submarines, Saboteurs and other devices and persons of that type. The organization expanded steadily: from 5 - 10 messages a day in April 1944 the traffic rose to about 100 a day in the Spring of 1945.
The earliest Bonito day broken was March 23rd, though the original break was of an April day; 3 pairs were broken in April and 2 in May. On comparatively few days was there sufficient traffic to make breaking possible and no very great interest was in any case displayed in the results. In June we had no success, probably through not having tried the correct Reflector combination. By July the Small Battle Units were becoming active and much more interest was displayed in the possibilities of Bonito as a result of which 23 days of July and all of August were broken. On September 1st Bonito ceased to throw-on.
This was a sad blow. Cribs were bad and for the next month and a half we made little progress: the only available reencodements came from Bloater and were extremely difficult. 6 days in all were broken in September with great difficulty and 4 in early October.