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Puzzle Series Vol. 5: Slitherlink

Loopy for the loops, we are.

Dark blue icons of video game controllers on a light blue background
Image credit: Eurogamer

I had to be forced to play it. Forced, because my life had been taken over by 1994's Mario's Picross, run on a Gameboy emulator. This was November last year, and it was my first encounter with the block filling puzzles, each so perfectly formed and satisfying to complete. What more could I want from my spare-time fiddling?

But the good Reverend Campbell in his liturgical wisdom forced me to take a break from the Picross frenzy and check out Hudson's fifth game in their Japanese Puzzle Series, Slitherlink. I had a quick look, found the concept less immediately obvious than Picross, and immediately went back. I was on Picross 2 by then, and taking on the huge grids of Wario's puzzles, where wrong answers were ignored to make the challenge even more tough. I can't remember what it was that had me give Slitherlink another go, perhaps more reverential pestering, but, well, I haven't done a Picross since.

I've completed 241 of them so far. While the earlier puzzles can be completed in less than three minutes, I'm now in the fourth difficulty level, due to start puzzle 22, and they're now up to about an hour per grid. Factor in going back to re-do earlier puzzles for the satisfaction of proving how much better at them I am now, and there's been at least 150 hours spent with this wunder-game over the last three or four months, with at least another 100 to go.

Meet the family

Aw, a 6x6. So delightfully simple, and yet so monstrously satisfying to finish in under 30 seconds. I am the best!

What are they, you ask? You might well have seen them before. They occasionally appear in the newspaper puzzle pages, alongside the vastly inferior Sukodu. My mum was visiting at the weekend, and as ever had a book of Suckodu puzzles in her handbag in case she got bored. I had my DS in my pocket for the same reason. It's not that my family's boring - it's that we have a very low boredom threshold, and are always prepared for the worst.

Er, there was a point to this. Her book contained the occasional Slither Link, under some idiotic name like, "Loop the Loop". They're around.

You begin with a grid, with a few numbers scattered about in the squares. The task is to fill in a single connecting loop that touches the edges of each numbered square the number of times that, er, the number on it says. So, say there's a 3, the square it's in will need three edges to be filled in. If it's a 0, then none, obviously. Fill in the red lines, X out the rest. Put a 0 and a 3 next to each other, and you know which three sides of the 3 must be filled in, right? And that's how it works: you start to see these patterns, these techniques, and the logic of your available moves becomes gloriously apparent.

Hudson have taken this simple puzzle, and put it on the DS in the most perfect way imaginable. It is, without hesitation, the best puzzle game I've ever played.

Learning curves

When I first began, ploughing through the first 20 games - the 6x6 grids - was fairly elementary. It only took me four or five minutes to complete each, and I felt like the master of the gaming world. Then came the 10x10s, which were a shock. Suddenly, with so much extra space (over twice as big, see), it wasn't quite so elementary to dump the lines in where they belonged. How I laugh at my poor, innocent self as I reflect on those days. What I previously knew was no longer good enough. I had to learn new methods, new techniques. And before I had these mastered I was experimenting with the dotted blue lines it lets you draw in. I was guessing, learning by trial and error. Each puzzle took between 10 and 15 minutes, and my brain was getting bigger.

The top screen will show you four of the most important techniques for avoiding mad guessing and blue line-based stumbling.

By the time I'd made my way through 90 of these, they were only taking 5 to 10 minutes, and the blue lines were history. And then suddenly it was 18x10. (The levels don't in fact divide by grid size. It's somewhat ambiguous as to how exactly the split is made). Then the third section changes from 18x10 to a whopping 24x14 two thirds of the way through. By now a grid had more white spaces than numbers, and each was a 15 to 20 minute task. More than a bus ride. But now I was discovering even more fantastic techniques for approaching the puzzles. Cranium swelling.

The game gives you tips like: if two 3s are diagonally next to one another, you can fill in the opposite corners on each; or: two 3s alongside each other will have their three vertical edges (including the shared one) filled in, plus Xs above and below the middle line. But there are loads more. They're horrible to explain in text. Proof: If you have a line pointing to a 2, with a 3 diagonally next to it, then you can fill in the opposite corner of the 3. As odd as they sound, they became instinctive, my eyes scanning the screen like a puzzling hawk, spotting recognisable groupings of numbers, or spaces I could eliminate to prevent the line from looping too soon, then swooping down, stylus in my talons, and attacking my prey.

Come puzzle 18 of the final block and - surprise! - 36x20. Twenty times bigger than the original puzzles, and each taking between 45 minutes to an hour. These are my current foes, most nightmarish because a single mistake is near impossible to spot, meaning finding yourself in a dead end often means restarting.

But when I go back to those 10x10s, they take less than two minutes, and that's only because it's as fast as I can tap. What I know now dwarfs what I knew then. I've learned. I've grown as a person. I'm your king! Well, I'm especially good at Slitherlinks.