A Puzzling War

Join us as we delve into the puzzling world to see what we can learn about the codebreakers of World War II and how they shaped one of our favourite pastimes – puzzling!

Morse and More

We’ll have to step a little further back than the war to look at how internationally recognised codes and communications grew in popularity. Invented by Samuel Morse in 1844, Morse Code is a versatile way to communicate without words.

Using dots and dashes to replace letters and numbers, Morse Code allows you to transmit a message no matter what situation you’re in – whether by a telegraph wire as an electronic communication or banging out SOS distress signal by hitting an object in an emergency.

Morse Code Guide | A Puzzling War

Morse Code, formed from lots of dots and dashes that were tapped at super speed to convey messages.

Morse Code via radio communication played a vital role in military and naval history, particularly back in the late 19th and early 20th-centuries when it wasn’t possible to transmit voice over the radio. The code and radio transmission even helped troops in the wars to get long-distance messages to each other when in the field – it wasn’t always possible to build telegraph wires in time with how quickly the troops moved!

Believe it or not, Morse Code was still used for maritime distress up until 1999! Although no longer used and monitored, some military and naval personnel are still trained in Morse Code in case it is needed.

Morse's Telegraph Station | A Puzzling War

Morse’s Telegraph Station, exhibited at the PTT Museum in Belgrade, Serbia.

Image: By Milica Buha - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=77603211

Curious Cryptography

Of course, the use of coded communications didn’t just spring up in time for WWII. There have been centuries of cryptography in various forms; looking back through history, a number of popular cipher techniques crop up:

  • The Substitution cipher, where letters would be substituted from the normal alphabet to a ‘cipher alphabet’ to create hidden messages;
  • The Caesar Cipher, where the letters in the alphabet are shifted so A=E, B=F, C=G, etc. – possibly the simplest cipher;
  • The Book Cipher, where the sender and receiver decide on a book to use as their key (the Bible proved popular) and the code would point the receiver to certain pages and passages to convey the message.

A Caesar Cipher | A Puzzling War

A Caesar Cipher with a right shift of three… Can you figure out what your name would be if you followed this method?

This got a little trickier in the lead up to both WWI and WWII, as more advanced techniques were implemented, and mechanical cipher machines were built. Although codebooks and manual techniques were still used occasionally, these machines allowed encrypted messages to be created at faster speeds and with more complex ciphers.

One well known electromechanical rotor machine, which caused a lot of problems for the allies in the early stages of WWII, was the Nazi-favoured Enigma.

An Enigma Cipher Machine | A Puzzling Autumn

An Enigma cipher machine, like the ones used by Nazi Germany in WWII. The set of letters at the top would light up when the bottom keys were pressed.

The cleverly designed Enigma allowed the user to type in their covert message as normal, and the machine would light up the letters it was substituting, so another person would write down the code to create the encrypted message. All the receiver would need to do is enter the encrypted message into their Enigma, and the real information would be revealed.

It may not seem too tricky to crack for the boffin codebreakers who intercepted these communications, but the Nazis had a trick up their sleeves as they developed the machine – the code changed daily. It may have hampered the efforts of the allied cryptanalysts, but it didn’t stop them from cracking it in the end…

Bloomin’ Brilliant Bletchley Park

One place you can’t avoid talking about when it comes to wartime codebreaking is Bletchley Park; ironic, considering how few people knew what classified operations had taken place there until the mid-1970s!

Bletchley Park mansion | A Puzzling War

Bletchley Park mansion in Buckinghamshire, home to some of the top codebreaking minds during WWII.

The historic country house and estate in Milton Keynes housed the Government Code and Cypher School during WWII. The best and brightest were recruited to play their part in the war effort by using their code-breaking skills to turn encrypted enemy messages into vital military information.

The personnel at Bletchley formed a massive library of index cards, filled with encrypted and deciphered information that could prove useful against the Nazis. It wasn’t just German signals that were monitored, though – teams were set up to keep their eye on Italian, Soviet and Japanese coded messages too.

Punched Card Machines and Index Storage |  A Puzzling War

Photos from inside Bletchley Park, taken in 1945, showing the punched card machines and part of the extensive storage library for the Central Index.

Machines were invented to counteract the methods used by the enemies, including the Bombe – developed from the Polish machine known as Bomba and initially designed by now-famous recruit Alan Turing.

The Bombe would help the allied codebreakers to discover the daily settings of the German Enigma encryption machine, allowing them to overcome the previous frustrations of having to try to crack the new code every day before they were even able to decipher the crucial transmissions.

Rebuild of the British Bombe | A Puzzling War

A rebuild of the British Bombe at Bletchley Park.

At its peak, Bletchley Park had nearly 10,000 personnel – both men and women – all of whom were sworn to secrecy after signing The Official Secrets Act. They couldn’t divulge the work they were doing to anyone – even family or colleagues stationed in other areas of the base.

The secret was kept for nearly 30 years after the war ended, until the publication of The Ultra Secret by F. H. Winterbottom in 1974, which sparked discussions in the public’s knowledge about what really happened. It still took until 2009 for any Bletchley personnel to be officially recognised for the work they did.

However, many former students and employees still kept themselves bound in silence – they did swear themselves to secrecy, after all – and took the truth about their wartime activities to their graves.

Cracking Cryptograms

How has this inspired our puzzling pastimes, we hear you ask? Well, a popular puzzle seen all through the brainteasing world is the cryptogram.

A Cryptogram | A Puzzling War

A Cryptogram puzzle! Can you crack it? (Scroll to the end to find the solution!)

Cryptogram puzzles give you a string of encrypted text, and your challenge is simple – you’ve got to crack it! Often, these ciphers are easy enough to crack without too much of a headache, unlike the original ciphers used in the military or to hide personal secrets.

Admittedly, the history of the cryptogram spans way beyond World War II. These puzzles surfaced in the court of Merfyn Frych ap Gwriad, a Welsh King who died in 844AD, and were a popular pastime for monks in the Middle Ages. In fact, the famous 13th-century monk Roger Bacon even wrote a book about ciphers!

Following the pattern of historic authors loving a good mind-boggling puzzle, one big advocate for cryptograms was Edgar Allen Poe, who takes a lot of responsibility for popularising the puzzles and getting them featured in magazines.

Edgar Allan Poe | A Puzzling War

Edgar Allan Poe, the famous 19th-century author (and part time cryptanalyst).

Watch and Learn

The brave work of these super-secret codebreakers hasn’t just impacted our brainteasers but has also inspired popular culture in the decades since. Countless television shows, films, podcasts and books have been created to tell the tale of these wartime heroes.

We’ve mentioned before how much our Resident Wordsmith Rachel enjoyed sitting down and trying to tackle the mind-boggling codes in Sinclair McKay’s Bletchley Park Brainteasers quiz book. But here are three other ways we’ve enjoyed adding a little bit of crypto history into our lives (apart from on our Spy Mission Trails, of course).

The Bletchley Circle

The Bletchley Circle was a popular television series following the post-war lives of four female codebreakers at Bletchley Park.

The Bletchley Circle | A Puzzling War

The Bletchley Circle (2012-2014) and The Bletchley Circle: San Francisco (2018).

Set seven years after the war, Susan (Anna Maxwell Martin) learns of a spate of killings in London and notices a pattern in the crimes. Unhappy with how these cases have been handled, strong>she gets back in touch with her colleagues Millie (Rachael Stirling), Lucy (Sophie Rundle) and Jean (Julie Graham) to ask for their help.

Susan’s friends are initially sceptical, after putting their deciphering time behind them and moving on with their lives. But, eventually, the four women club together to use their unique set of skills to solve a deadly mystery.

There were two series original series, broadcast by ITV between 2012-2014. It wasn’t renewed for a third series, but a popular spinoff, The Bletchley Circle: San Francisco, was released in 2018 featuring Millie and Jean using their code-breaking and mystery-solving skills across the pond.

You can watch The Bletchley Circle and The Bletchley Circle: San Francisco on Amazon Prime.


Enigma is a fictional novel by Robert Harris, first published in 1995, and explores the work of protagonist Tom Jericho as he tries to crack German Enigma ciphers.

Enigma Novel | A Puzzling War

Enigma by Robert Harris (1995).

A young mathematician and talented cryptanalyst, Tom is called back to work at Bletchley Park after taking time off sick to recover from the pressure of his job. But, his return to the office is vital: they’ve been locked out of the Naval Enigma and need his top-notch brain!

Tom jumps back into it to find a workaround to get the team back into the Enigma, while juggling his work-based stress, deciphering a stash of curious-cryptograms he stumbled upon and trying to work on a rollercoaster relationship with his ex-girlfriend, Claire.

Although it doesn’t show an accurate portrayal of what it was like to work at Bletchley Park, the high-paced novel will have you on your toes with its twists and turns.

You can get your hands on Enigma via all good booksellers.

The Imitation Game

Speaking of the Enigma machine, the award-winning 2014 filmThe Imitation Game follows the life and work of Alan Turing, the famous mathematician who built a machine to crack the Enigma.

The Imitation Game | A Puzzling War

The Imitation Game (2014).

Alan Turing(Benedict Cumberbatch) joins the team at Bletchley Park at the start of the war and works with a team of cryptographers who are trying to crack the Enigma machine used by the Germans to send their coded messages.

Turing works in isolation to create a machine that will break the code, which gets funded directly by Prime Minister Winston Churchill. But he faces a problem – the Germans change the code daily, making it seemingly impossible to crack. After having an epiphany, Turing takes a different path to recalibrate the machine to finally discover what information is being transmitted by the enemy.

The film, adapted from the 1983 biography Alan Turing: The Enigma by Andrew Hodges, takes a lot of creative licenses and isn’t historically accurate, and skims around the subject of Turing’s personal life. However, it honours the important work done by Turing and the rest of his team during this dark time in our history.

You can watch The Imitation Game on Amazon Prime.

Bonus Historical Insights

Okay, we know we said three ways we’ve been exploring the wartime code-breaking history… But, if you’re interested in learning more about this time in British history, the team at Bletchley Park have created a fantastic series of podcasts featuring interviews and inspirational stories from those who were directly involved or knew people who joined in with this secretive area of the war effort.

Bletchley Park is now open as a heritage attraction which you can visit to unlock more fascinating tales and see the clever machines used up close.

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Treasure Trails Puzzle Academy Logo | A Puzzling Autumn

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