How to Think Like Sherlock (13 page)

Know your accents

Having the ability to take on a new voice is a brilliant way to mislead. Holmes was presumably masterful in Norwegian and in ‘His Last Bow’ passed himself off as a convincing Irish-American.

Have a back story

Know your alter ego inside out so that if you are challenged, you may maintain it effortlessly. It is difficult to imagine that Holmes could have so effectively masqueraded as Sigerson unless he had a deep knowledge of the Norwegian’s life story.

Commit to the part

At times you may be forced to go the extra mile to maintain a deception. One of Sherlock’s favourite techniques was to stoop in order to appear older. ‘It is no joke when a tall man has to take a foot off his stature for several hours on end,’ he was forced to complain. Even more startlingly, in ‘The Adventure of Charles Augustus Milverton’, Holmes found himself engaged to a housemaid called Agatha, all in the cause of maintaining the illusion of his disguise.

Quiz 16 – Elementary, dear reader … Part III

A mugger accosts a wizened old riddler in one of Soho’s most notorious backstreets.

‘Give me your money,’ demands the attacker.

The riddler duly takes out his wallet and to the amazement of the thief, counts out a number of pound notes. ‘This is all I have in the world,’ he says. ‘If you can guess the ages of my three sons from the clues I give you, I’ll surrender it without a struggle. If you get it wrong, I’ll fight you for it. I might still lose my money as I am not as young as I once was, but I have spirit and I’ll make sure you get a good kicking in the process. Are you game?’

The bewildered thief nods.

‘Right. If you multiply the ages of my sons together, you get thirty-six. Add them together, and it equals the number of pound notes you’ve just watched me count. How old are they?’

The thief looks perplexed, numbers spinning chaotically inside his brain. A minute or two later, the riddler says, ‘In fairness, I haven’t given enough information for you to answer. One more clue. My eldest boy’s mathematics tutor is called Professor Gibson. Now that should be all the information you require.’

The thief is as confused as ever. After a few moments he says, ‘No, it’s no good. I can’t possibly figure it out. Explain it to me or I shall lie awake all night wondering about it.’

‘With pleasure,’ says the riddler, before felling his assailant with a swift kick to the shin and waddling off into the safety of the night.

So what answer should the mugger have given to claim the riddler’s money and save himself a nasty bruise?

Breaking the Code

‘I am fairly familiar with all forms of secret writings, and am myself the author of a trifling monograph upon the subject, in which I analyze one hundred and sixty separate ciphers.’

‘THE ADVENTURE OF THE DANCING MEN’

Cryptography (from the Greek for ‘hidden writing’) is the science of code- and cipher-creating, while cryptanalysis is concerned with breaking them. In Holmes’s world, filled with deceits and intrigues, a thorough comprehension of cryptanalysis was an invaluable way to discover useful information.

Some basics to begin with – a code and a cipher are not the same:

In a code, each word or phrase is replaced by another word, phrase or symbol. Both the message sender and recipient must know what the coded words, phrases and symbols mean either by prior agreement or through use of tools such as code books. A code is a secret language.

In a cipher, each letter is either replaced by an alternative letter, number or symbol (a substitution cipher) or the letters are shuffled about (a transposition cipher). Plaintext is the name given to the information you wish to communicate, while ciphertext is what is actually sent.

Here are a few of history’s more famous codes and ciphers:

The Caesar cipher

(also known as the Caesar shift)

This was supposedly devised by Julius Caesar for use by his troops. It involves shifting letters along the alphabet by a set number of positions. If you move the alphabet by one position, for instance, a is signified by b and b is signified by c. So the word cat would be communicated as dbu. Shift two positions and a is signified by c and b is signified by d (with cat becoming ecv). There are a potential twenty-five Caesar shift alphabets.

The transposition code

In its simplest form, this involves writing your message into a grid of suitable size, which is then read from a predetermined start point and in a particular direction. Can you decode the following message?

Start at the bottom right-hand corner and read each column from bottom to top. The message is ‘The enemy will attack in one hour.’

Pig Latin

This technique was probably developed in the early Victorian era. Its basic rules are simple. If a word starts with a consonant (or consonant cluster), move that to the end of the word and add the letters ‘ay’ after it. If a word begins with a vowel (or a silent consonant), add ‘way’ to the end. Try deciphering this:

ewarebay ethay angryway anmay inway ethay oldway athay.

The message reads: ‘Beware the angry man in the old hat.’

The pigpen cipher

A centuries-old cipher that uses four simple grids containing all the letters of the alphabet:

When writing their message, the sender replaces each letter with the relevant fragment of grid. Hence ‘Beware’ becomes: