Testery

Key takeaways

Testery belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Testery to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Testery from memory before moving on to harder problems.

Reference excerpt

The Testery was a section at Bletchley Park, the British codebreaking station during World War II. It was set up in July 1942 as the "FISH Subsection" under Major Ralph Tester, hence its alternative name. Four founder members were Tester himself and three senior cryptanalysts: Captain Jerry Roberts, Captain Peter Ericsson and Major Denis Oswald. All four were fluent in German. From 1 July 1942 on, this team switched and was tasked with breaking the German High Command's most top-level code Tunny after Bill Tutte successfully broke Tunny system in Spring 1942.

Methods The Testery used hand decrypting methods to break Tunny traffic. Within one year of its foundation, the Testery had deciphered 1.5 million texts by these methods. By the war's end in Europe in May 1945, the Testery had grown to nine cryptanalysts, a team of 24 ATS, a total staff of 118, organised in three shifts working round the clock. The logical structure of the Tunny system was worked out by mathematician Bill Tutte in the spring of 1942. Tunny had 12 wheels, and was more advanced, complex, faster and far more secure than the well-known 3-4 wheeled Enigma machine. The Germans were convinced that the Tunny cipher system was unbreakable. Tunny was the cipher system which carried only the highest grade of intelligence: messages from the German Army Headquarters in Berlin and the top generals and field marshals on all fronts. Some were signed by Hitler himself. Tens of thousands of Tunny messages were intercepted by the British and broken at Bletchley Park by Captain Roberts and his fellow codebreakers in the Testery. These messages contained much vital insight into top-level German thinking and planning. After the Testery had been breaking Tunny for a year by hand, the Newmanry became active from July 1943 under Max Newman. Mathematicians in the Newmanry used machine methods to speed up breaking Tunny. Early on, a machine called Heath Robinson was produced, to help speed up one stage – breaking of the chi wheels, but the Robinson was slow and not reliable. In February 1944 a new machine called "Colossus" became operational; it was the world's first electronic computer. Colossus was designed and built in only ten months by Tommy Flowers of the G.P.O. (Post Office). This had far greater capacity and speed than the Robinson and so the whole breaking process became much faster. The Colossus was essential for making the very fast counts needed to work out the "de-chis", but the psi-wheels and motor-wheels were still broken by hand in the Testery. The Testery was hand code-breaking Tunny for 12 months before the Robinson machine was produced and for 19 months before Colossus operated. With the help of the Newmanry, the Testery broke up to 90% of the traffic given to them to work on in the Colossus period. The information provided by Tunny enabled the Allies to ascertain German movements, saving thousands of lives at critical junctures such as D-Day and the Battle of Kursk in the Soviet Union. General Dwight D. Eisenhower gave the best summary after World War II. He said that "Bletchley decrypts shortened the War by at least two years". Tunny played a very important role in all of this, a war which was costing at least 10 million lives a year. A great deal of this was down to Bill Tutte. The story of Enigma (declassified in the 1970s) is well known, but the story of Tunny, Germany's top-secret cipher machine, was only declassified in the 2000s. Most of the cryptanalysts in the Testery died before they could tell their stories. For the first time, on 25 October 2011, a BBC Timewatch programme titled Code-breakers: Bletchley Park's Lost Heroes, about the Testery, Tunny, Bill Tutte and Tommy Flowers, was produced, featuring testimony from Jerry Roberts.

List of senior executives and codebreakers on Tunny in the Testery Ralph Tester: linguist and head of Testery (not a codebreaker) Peter Benenson: codebreaker John Christie: codebreaker Tom Colvill: general manager Peter Edgerley: codebreaker Peter Ericsson: shift-leader, linguist and senior codebreaker Peter Hilton: codebreaker and mathematician; joint appointment with the Newmanry Roy Jenkins: codebreaker (later moved on to be a wheel setter) Victor Masters: shift-leader (not a codebreaker) Donald Michie: codebreaker; joint appointment with the Newmanry Denis Oswald: linguist and senior codebreaker Jerry Roberts: shift-leader, linguist and senior codebreaker Jack Thompson: codebreaker By the war's end in Europe in May 1945, the Testery had grown to nine cryptanalysts, a team of 24 ATS, a total staff of 118, organised in three shifts working round the clock.

See also Allen Coombs Cryptanalysis of the Lorenz cipher Cryptanalysis of the Enigma

References

Bibliography Roberts, Jerry (2006), "Major Tester's Section: The significance of breaking Tunny", in Copeland, B. Jack (ed.), Colossus: The Secrets of Bletchley Park's Codebreaking Computers, Oxford: Oxford University Press, pp. 249–259, ISBN 978-0-19-284055-4 Gannon, Paul (2006), Colossus: Bletchley Park's Greatest Secret, London: Atlantic Books, ISBN 978-1-84354-331-2 Good, Jack; Michie, Donald; Timms, Geoffrey (1945), General Report on Tunny: With Emphasis on Statistical Methods, UK Public Record Office HW 25/4 and HW 25/5, retrieved 15 September 2010 That version is a facsimile copy, but there is a transcript of much of this document in '.pdf' format at: Sale, Tony (2001), Part of the "General Report on Tunny", the Newmanry History, formatted by Tony Sale (PDF), retrieved 20 September 2010, and a web transcript of Part 1 at: Ellsbury, Graham, General Report on Tunny With Emphasis on Statistical Methods, retrieved 3 November 2010 Kenyon, David (2019), Bletchley Park and D-Day: The Untold Story of How the Battle for Normandy Was Won, Yale University Press, ISBN 978-0-300-24357-4

External links "Lorenz: Hitler's "Unbreakable" Cipher Machine" on YouTube; 11:42 minutes (HTML5) "Bletchley codebreaker Raymond 'Jerry' Roberts appointed MBE" December 2012 on BBC Online; (Adobe Flash)

Worked examples

Example 1 — a first encounter with Testery

Start with the simplest possible case. Write down what Testery claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Testery before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Testery ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Testery

In research: Testery appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Testery in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Testery is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1942 establishments in the United Kingdom, 1945 disestablishments in the United Kingdom, Bletchley Park, so understanding it makes those chapters shorter.
In everyday life: Look for Testery outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Testery in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Testery means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Testery out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Testery in simple terms?

The Testery was a section at Bletchley Park, the British codebreaking station during World War II. It was set up in July 1942 as the "FISH Subsection" under Major Ralph Tester, hence its alternative name.

Why does Testery matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Testery?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Testery.