OBITUARY - Brian Townend

THE TIMES
March 02, 2005

OBITUARY - Brian Townend
------------------------
Cryptanalyst who learnt Japanese from a destroyer's logbook and broke the
enemy's naval codes

AFTER reading Greats at Oxford, Brian Townend was recruited by the Foreign
Office at the outset of the Second World War and was sent to the
Government Code and Cipher School at Bletchley Park to train as a
cryptanalyst. As such he was to make a contribution to the prosecution of
the war in the Far East through the reading of Japanese encrypted signal
traffic. For this purpose he learnt Russian and Japanese, both with a very
specialised vocabulary. Indeed his Japanese was learnt from the logbook of
a captured destroyer of the Imperial Navy.

In 1942 he was posted as a civilian attached to the Royal Navy
intelligence staff at Kilindini in Kenya, where one of the preoccupations
was breaking the ciphers with which the Japanese Merchant Navy
communicated with the Imperial Navy and protected its shipping routes.

Allied codebreakers had already, in May 1940, broken one code, dubbed
JN39, causing the Japanese to change it. Then early in 1941, before
America had been drawn into the war, the FBI had stolen a copy of the
changed codebook from a Japanese freighter in San Francisco harbour. When
they found out, the Japanese promptly changed the code again.

The new code, named JN40 by the Allies, was worked on at Kilindini by John
McInnes and Townend, who in September 1942 had a lucky break when a
Japanese operator, who had omitted a ships position from his original
message, reinciphered it with the same keys, including the longitude and
latititude, instead of sending that detail in a separately encrypted
message. A comparison of the two messages gave McInnes and Townend the
vital clues to the nature of the code, and their way into it.

By November 1942 the codebreakers were confident of breaking every
message, enabling all enemy shipping to be tracked and attacked. McInnes
and Townend subsequently broke two more systems, the previously
impenetrable merchant shipping cipher JN167, and the navigation warning
cipher JN152.

Later in the war Townend was posted to the Far East intelligence staff at
Colombo. There he met his wife Bett, a Wren, also Bletchley Park trained.
She worked as a programmer of the early decryption computers.

After the war Townend became a teacher, first at the Dragon School,
Oxford, then as a classics master at Sevenoaks School, where in the late
1960s he became head of music.

Brian Townend, wartime codebreaker and schoolmaster, was born on May 2,
1917. He died on February 3, 2005, aged 87.


http://www.timesonline.co.uk/article/0,,60-1506404,00.html



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