Meet the crossword setter, Professor Serpent: ‘There’s no point in making it too hard or too easy’

Jack is a name that pops up in the Genius, the Guardian’s monthly advanced puzzle. Jack is also known as Jason Crampton, who is also known as Skipjack but most often as Serpent – in the Independent, the Inquisitor, Enigmatic Variations and the Listener. Oh, and also in subscription magazine the Magpie, where he is on the editorial team. Let’s meet Serpent. Or Jack.

Hello Jack. Has the pandemic generated extra interest for the Magpie magazine, or for tougher puzzles more generally?
Absolutely! The number of Magpie subscribers increased last year, as has the number of solutions we receive each month. The number of subscribers to the Cracking the Cryptic YouTube channel – run by Mark Goodliffe and Simon Anthony, who co-founded the Magpie – has grown enormously.

Happy to hear it. Do you have a favourite of your own puzzles?
Of my blocked puzzles, perhaps my favourite is the one I wrote following the death of my dog, Bo: every across entry contained his name and the unchecked cells in the central row spelt out GOODBYE.

Here’s a review of it (and a link, which might work on some devices). When did you get the crossword bug?
I started solving cryptic crosswords at university. I got the setting bug when I attended one of Boatman’s masterclasses.

Like others we’ve spoken to here. And how did you choose your pseudonyms?
Serpent is a cryptographic algorithm, so it was connected to my day job as a professor of information security.

I had intended to choose other cryptographic algorithms if I needed further pseudonyms but then decided that words related to Serpent would be better, hence Basilisk. Skipjack is another cryptographic algorithm, but everyone thought it was a reference to tuna! And Jack is a contraction of Skipjack.

Professor, eh? Any other setters you know of in the same echelon?
At least a couple: Monk is a professor of mathematics at Leeds University and Sabre – setter of brilliantly fiendish barred puzzles – is also a maths professor, at Arizona State University.

Ah, Sabre. My old foe. What makes a successful clue? Or an unsuccessful one?
I think successful clues contain at least one of the following: humour, misdirection, oblique definitions and inventive wordplay. An unsuccessful clue contains inaccurate cryptic grammar or definitions.

A weak clue uses pedestrian definitions and a list of wordplay instructions that simply have to be followed.

We’ve talked here before about how the business of crosswords can involve as much maths as it does literacy. What’s the overlap between your old day job and the puzzles?
The wordplay can be thought of as expressions in a formal language, in which wordplay elements represent variables and wordplay indicators represent operators on those variables. I find it very helpful to think of clues in this way when I’m analysing whether the cryptic grammar of a clue is correct.

Setting a crossword is a bit like setting an exam: there’s no point in making it too hard or too easy, so there have to be a few entry points.

Also, the process of preparing puzzles for publication, especially when one is trying to first get published, has similarities with preparing academic papers for submission. There are many reasons a paper or a crossword can be rejected, so it’s important to give an editor as little as possible to find fault with.

Quite. Now, you’re unusual in using the same name in your weekday puzzles as your tricky weekend ones. How do you alter the level of intricacy?
Many barred puzzles contain quite obscure words, limiting the possibilities for disguising the definition.

Clues for these words often end up as a list of instructions for constructing the answer tacked on to a straightforward definition. I think I’m unusual in also trying to avoid obscure vocabulary in my barred puzzles: I try to populate my grids using a rather limited dictionary.

This means I can write clues that are similar to those that I write in blocked puzzles. The disguise in the surfaces – plus any thematic clueing gimmicks – suffice to make the clues difficult enough.

What are the tools of your trade?
Qxw for grid construction. Crossword Compiler for assembling puzzles in a format acceptable to editors. The Chambers dictionary and thesaurus apps for my phone/tablet.

Qat for pattern-matching and searching, which is absolutely essential for barred puzzle construction. Qxw and Qat are both available from Quinapalus’s website. Oxford Dictionary of Quotations and Wikipedia for barred puzzle research.

Qat is remarkable. What kind of people do you think are attracted to barred tough puzzles?
I think there are people who love crosswords but, after years of practice, find the daily cryptics too easy; they relish the additional challenge of solving puzzles with clueing gimmicks.

Others aren’t that interested in daily cryptics but love difficult logical puzzles. For them, it is the endgames of the barred thematic puzzles that are particularly interesting.

I’m in the former camp, so my barred puzzles tend to have quite difficult clues but relatively straightforward endgames. Other setters write comparatively straightforward clues but the endgames are extremely intricate and things of real beauty.

How do people respond when you tell them that you’re a crossword setter?
In pretty much the same way as when I used to say I was a professor in a maths department! “You must be really brainy” or “I could never do maths/solve crosswords”.

But they’re also fascinated by it and really interested in how I go about setting them. I try to persuade those who don’t solve crosswords to try them. I tell them they only need a reasonable vocabulary, some patience and an interest in how language can be used in imaginative ways.

What’s the future for cryptic crosswords?
It’s really difficult to say. I think there will always be a niche market for tough barred puzzles. They will survive in specialist magazines like the Magpie, even if they disappear from the newspapers.

There are some brilliant young setters of such puzzles and new ones are always emerging. However, crossword puzzles are relatively expensive to produce compared with puzzles such as sudoku and kakuro, so I could see daily cryptics being viewed as a luxury that newspapers can no longer afford with advertising revenues declining. I hope I’m wrong!

But it may be that specialist online crossword sites will emerge that charge subscribers for daily puzzles. I hope there would be enough people willing to pay for puzzles of the quality found in the Guardian and the other broadsheets.

Many thanks to Serpent/Jack, whose suggestion for our collaborative playlist Healing Music Recorded in 2020-22 to Accompany a Solve or Even Listen to is from his old schoolfriend Richard March, who “has been involved in recording cover versions of classic songs to raise money for musicians unable to earn a living during the pandemic”.

The Shipping Forecast Puzzle Book by Alan Connor, which is partly but not predominantly cryptic, can be ordered from the Guardian Bookshop.