CAROL’S CUT-OUT-AND-KEEP GUIDE TO SUKO

THE RULES OF SUKO

THE name ‘Suko’ sounds like a mini version of Sudoku, and that’s exactly what it is. The nine boxes must be filled in with the digits 1 to 9.

In the nine-box grid, there are four numbers in white circles. When the four boxes overlapped by each circle are filled in, their numbers have to add up to the total in the circle.

Now here’s the part I really love. The nine boxes are shaded in three colours — pale, medium and dark. And there are three corresponding circles underneath, each containing a number. Your challenge is to make sure each set of coloured squares adds up to the matching target. Here’s the key: you can use each digit, 1 to 9, only once. That simple fact will help you unpick any Suko.

JARGON BUSTER

IN SUKO, and other puzzles such as Killer Sudoku, boxes within the main grid are grouped together. Sometimes they’re shaded darker, sometimes they’re outlined in dotted or heavy lines. These groups are called ‘cages’.

THE SUKO SECRET

THE lowest target for any group of three digits is six (1+2+3). The lowest target for any group of four digits is ten (1+2+3+4). That means the target totals are giving you lots of clues — and the more you play Suko, the more you’ll learn to spot the giveaway numbers. For example, if the target for a cage of four is 11, the four digits must be 1+2+3+5 (go on, check it and you’ll see I’m right — no other four numbers add up to 11).

Once you know where the 1, 2, 3 and 5 are, you also know that the other five boxes contain 4, 6, 7, 8 and 9.

High targets are great clues, too. If a three-digit group adds up to 24, it must contain 7, 8 and 9. No other combination of the numbers 1 to 9 will add up to 24.

Tackle a few of these puzzles and you’ll soon have lots of combinations off by heart. It’s a wonderful example of how puzzles make us look at numbers in a different way.