GCHQ Christmas card asks recipients to decrypt picross puzzle

People who successfully solve the puzzle can write in, and a winner will be chosen from the correct entries

George Osborne speaking at GCHQ in Cheltenham
George Osborne speaking at GCHQ in Cheltenham

GCHQ is celebrating Christmas by revealing a hugely difficult brainteaser and asking people to take part.

The British spying agency has sent out its annual Christmas cards. And rather than including a picture of a festive scene, it features a grid of squares that must be deciphered and filled in to reveal a picture.

But even once that picture is solved, many more puzzles will be revealed. Decoding the first puzzle will lead on to a range of other ones, according to GCHQ.

The Christmas card puzzle can be found below, as well as on GCHQ’s website.

GCHQ explains that “In this type of grid-shading puzzle, each square is either black or white. Some of the black squares have already been filled in for you.

"Each row or column is labelled with a string of numbers. The numbers indicate the length of all consecutive runs of black squares, and are displayed in the order that the runs appear in that line.

"For example, a label "2 1 6" indicates sets of two, one and six black squares, each of which will have at least one white square separating them."

Participants are asked to send the solutions on to GCHQ by 31 January. The agency will then choose a winner.

The agency said that it had released the cards as a way of ensuring that the people on director Robert Hannigan’s Christmas card list were using their brains.

"This year, along with his traditional Christmas cards, Director GCHQ Robert Hannigan is including a brain-teasing puzzle that seems certain to exercise the grey matter of participants over the holiday season.

"The card, which features the 'Adoration of the Shepherds' by a pupil of Rembrandt, includes traditional Christmas greetings from Director on behalf of the department.

"However, unlike previous years, the 2015 card will contain a grid-shading puzzle and instructions on how it should be completed."

GCHQ has asked that people taking part donate to the NSPCC charity.

Click here to visit The Independent's crosswords and puzzles site

Register for free to continue reading

Registration is a free and easy way to support our truly independent journalism

By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists

Please enter a valid email
Please enter a valid email
Must be at least 6 characters, include an upper and lower case character and a number
Must be at least 6 characters, include an upper and lower case character and a number
Must be at least 6 characters, include an upper and lower case character and a number
Please enter your first name
Special characters aren’t allowed
Please enter a name between 1 and 40 characters
Please enter your last name
Special characters aren’t allowed
Please enter a name between 1 and 40 characters
You must be over 18 years old to register
You must be over 18 years old to register
Opt-out-policy
You can opt-out at any time by signing in to your account to manage your preferences. Each email has a link to unsubscribe.

By clicking ‘Create my account’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Already have an account? sign in

By clicking ‘Register’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Register for free to continue reading

Registration is a free and easy way to support our truly independent journalism

By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists

Already have an account? sign in

By clicking ‘Register’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Join our new commenting forum

Join thought-provoking conversations, follow other Independent readers and see their replies

Comments

Thank you for registering

Please refresh the page or navigate to another page on the site to be automatically logged inPlease refresh your browser to be logged in