GCHQ’s 2015 Christmas Puzzle: Meet the Nonogram, plus tips on how to solve one from a beginner

The last time GCHQ had an online puzzle hunt was in 2013 with their “Can You Find It” contest. The home page held an encrypted code made of five letters bundled into one group, with twenty nine groups in total. When I saw last year (December 2015) that GCHQ has released a cryptic puzzle on their Christmas card – it was exciting to see what type of puzzle would be released.

This time, there are again five individual puzzle stages but the last stage doesn’t hold just one puzzle but instead has five unique puzzles to solve. Here’s the reddit thread if you want to see all the puzzles that were encountered and how to solve them. The contest runs until January 31st 2016.

In this post, the focus is going to be on the first puzzle that was released – the grid puzzle. At first glance it looked strange – especially to someone who has never attempted a puzzle such as this before. Where to start on a puzzle such as this?


Meet the Nonogram – more well known by other names such as Picross, Paint by Numbers and well known in the UK as Griddlers.

The idea for a puzzle grid bloomed in 1987, when Non Ishida of Japan entered and won a competition where pictures were created on the side of a building by turning specific lights on and off. As all good stories go, there was another person Tetsuya Nishio who around the same time created a similar puzzle. Then in 1989, James Dalgety negotiated a license with Non Ishida to reproduce her puzzles throughout the world and subsequently brought it over to the UK for publishing in newspapers.

How to solve a Nonogram
– The numbers tell you where to go, similar to Sudoku but with a Nonogram you need to also physically mark off where you can’t go.

1) Don’t panic
2) This type of grid puzzle involves shading in boxes in order to reveal a picture. The hint numbers on the edges of the puzzle reveal where to shade in.
3) Find large numbers – in the case of the GCHQ puzzle, when the number 7 appeared it led to the creation of boxes in the corners of the puzzle (hinting at the beginnings of a QR code)
4) Mark the spaces where shading cannot occur (eg. if the hint number says seven boxes need to be shaded in – the eighth box cannot be shaded)
4) Find a row of numbers which sit comfortably in the puzzle (eg. the hint number suggests two blocks, another two blocks, followed by another two blocks, then a group of six blocks and one block on its own. Plus the spaces in between the boxes fit in).
5) One blocking is what I called it but there’s probably a name for it. See how this last box is shaded? The puzzle hints the last number in the row is a 1, which means the box to the left cannot be shaded in and can be marked with a X.
6) Don’t give up – there’s plenty of other tricks to solve a Nonogram. One which was good but tricky to use is called ‘Simple Boxes’ on Wikipedia.


#Notes: Modern Sudoku was thought to have emerged in 1979 from Indianapolis, US by Howard Garns. In 1984, this type of puzzle was picked up by Nikoli, a Japanese company who subsequently printed it in their magazines.

Happy New Year!
Essa 🙂


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