WHO WOULD believe that it is only three months since Su Doku turned up on the back page of T2? Only three months since this little Japanese puzzle came to Britain. Only three months since rows, boxes, columns and cells became topics to be shouted about over the breakfast table. Only three months since we started tearing out our hair and chewing through pencils, because try as we might, we can’t even make a dent in the “Difficult” ones. Or perhaps that’s just me.
It must be. As of this week, “Easy” Su Doku puzzles will be confined to Mondays. From your letters, your e-mails and the entries into the daily competition, it’s obvious that you have outgrown them.
So, Tuesdays will be “Mild”, Wednesdays will be “Difficult”, and Thursdays and Fridays will be “Fiendish”. Being personally a little terrified about all of this, I gave the puzzle’s creator Wayne Gould a call, to pick up some tips.
He’s a cagey one, Mr Gould. “There are a lot of methods you can employ,” he concedes, “but I wouldn’t want to give them away. I wouldn’t want to rob the puzzles of their mystery, you might say.”
I plead awhile, and Gould agrees to rob them a little. Rule One, he says, is to “slice and dice”. Slicing is when we look at a horizontal band of three boxes of nine cells. The same number (let’s say a 7) might appear in two of them, and frequently it will be immediately obvious where it should appear in the third. “I call that a gimmee,” says Gould. “Like with golf.”
Sometimes we have our two 7s, but have a choice of two or three cells into which the third could go. This is where Gould would bring in dicing, looking for clues from the vertical band as well.
Now. Pay attention. This is where it gets harder.
Sometimes, we can use these methods to find the third 7, even if we don’t know where one or both of the first two 7s are. Are you with me? In other words, you might know roughly where the first two 7s would be and, from there, be able to predict exactly where the third would be. Read that paragraph again a couple of times, if this is not sinking in. It took me a while.
It is this kind of thing, says Wayne, that makes The Times Su Doku so distinct from its competitors. His puzzles are constructed with clues that lead, logically, to a solution. Rival puzzles don’t work like this. Some can be solved only by guessing which numbers should go where. This is never required with The Times Su Doku. If you spot the clues, and you follow them successfully, you will reach the solution. And there is only, ever, one solution. “Other newspaper’s puzzles have slipped up on that,” notes our puzzle master, with just a trace of glee.
Look carefully at one of Gould’s puzzles and you will see that they always display a degree of symmetry. Other puzzles do not.
Similarly, his puzzles always have as few clues as possible. Gould likens this to Japanese paintings, exercises in simplicity which will depict a flower or a house with the bare minimum of strokes. “The Japanese would regard it as a matter of elegance,” he says. Such is the craftsmanship that goes into these things, a Su Doku in The Times will have between four and six fewer clues than a puzzle of equivalent difficulty elsewhere.
Should that one, quality, daily puzzle not be enough for you, fear not, for help is at hand. After the puzzles first appeared, it was a matter of hours before the first readers were phoning in, requesting a whole book of them. The Times Su Doku will thus be in all good bookshops from March 7, priced £5.99.
“I think it would be fair to describe pre-sales as unprecedented,” says Martin Toseland, publishing director of HarperCollins. “We’ve been quite bowled over by the demand.”
Should he wish to, it’s obvious that Gould could rattle off full instructions on exactly how to solve even the hardest of puzzles. Rather upsettingly, it is not something he is willing to do.
“Do you remember Rubik’s cube?” he asks me. “It sold thousands or millions, and everybody was fascinated. Then everybody bought this book that told them how to solve it and, lo and behold, they were finished with it, and they chucked it in a drawer. They thought the puzzle was solved. But actually, they hadn’t solved anything. They’d just learnt how to follow a set of instructions.”
Personally, I bought a Rubik’s cube, and bought the book, and still couldn’t solve the damn thing. I en-ded up swapping the stickers around.
Although Wayne does describe Su Doku as the Rubik’s cube of the pencil and paper world — the notion of boxes, in a sense, adds a third dimension to a two-dimensional puzzle — a similar strategy probably wouldn’t get me very far. I cajole and plead and beg a little more, and eventually he offers me a Rule Two.
Rule Two is “divide and conquer”. It’s all about breaking big problems into smaller problems. So, as Caesar did unto the Gauls, you must do unto your “Fiendish” Su Doku. “If you have a row with five empty cells,” he says, “look to see if you can chip two away into some kind of separate category.”
That way, the problem shrinks.
Even when we have empty cells, in other words, we may know more than we think we do. For example, within a box, you might have established that two numbers have to go into two particular cells, even if you aren’t certain which goes into which. The bottom left cells of a box, say, might have to take the numbers 1 and 2, even if you don’t have a clue which way round they should go. Divide and conquer means that, when you look at their row as a whole, you remember this. So, instead of trying to fit five numbers into five cells, you now only have to fit three into three. It might sound obvious but it’s an easy trick to miss.
When pressed, Wayne will admit to having as many as 20 little tricks and techniques like this up his sleeve.
The trouble is, I’m damned if I can get him to reveal any more of them. Many of you out there, no doubt, have evolved your own. Should you be willing to share them, let us know.
Failing that, I’ll get back to eating wood.
- Pre-order The Times Su Doku book (for delivery on publication, March 7) for only £5.09 (RRP £5.99) plus p&p. Call 0870 1608080
WHY WE LOVE IT
Jane Wenham-Jones (novelist), 41, Broadstairs, Kent
Su Doku is dangerous stuff. Forget work and family — think papers hurled across the room and industrial-sized tubs of correction fluid. I love it! Unlike a crossword, the solution to a Su Doku is always within your grasp as long as you sit there long enough.
My son says I am very boring about “those bloody numbers”. I have explained the benefit to brain and sanity and told him to be grateful I won’t be a nuisance in my old age. Though I did wonder if I were getting a touch obsessive when I heard myself shrieking: “How dare you move the Tippex! I need it here NOW.”
Dr Hilary Ockendon ( senior faculty member, the Mathematical Institute, University of Oxford), 63
Su Doku is regularly discussed over coffee in the Oxford Centre for Industrial and Applied Mathematics and a number of people are hooked. I try it when I have time, but I usually fail on the “fiendish” ones despite having been a cryptographer at GCHQ.
Pete Forman (software engineer), 45, West Sussex
I’ve written a Su Doku solving program on my computer and I input the numbers from T2. I solve it that way, paste the answers into an e-mail and send it in every day. That’s not cheating, is it?
Caroline Lord (actress), 28, London
I wait for a suitable lull at the café where I work as a waitress, sit down with the puzzle, happy in the knowledge that I may look like a geek, and begin to scan the top row from left to right. Immediately I forget all my other cares and only the attainable goal of a completed Su Doku puzzle remains. The sense of achievement on viewing your perfectly correct numbers is immense and you carry it with you for the rest of the day.
Anna Houston (housewife), 63, Enfield
I’ve been playing it since it began. It is different and it is addictive.
I can’t put it down until I have finished it. Sometimes it takes a few minutes; at other times it takes me up to several hours. I just have to finish it. I see it as a competition against myself — if I haven’t done it I feel stupid.
Kate Hilder (secretary), 27, Dublin
I love problem-solving that uses numbers. Crosswords don’t gel with me at all. So I’ve found myself working on Su Doku five days a week. The reasoning and the logic appeal to me. To me, maths was always logical and this works in the same way.
