I go through numbers one to nine. I start at number one and I see if there are any obvious places where it can go. I then repeat that for all the other numbers. In all the left-over empty boxes I write, using small figures, all the numbers that can possibly go there. Then I check the groupings of those. For example, if there is a row of five empty boxes and there are three of those that could only be numbers two, three or four, then I know that the other two empty boxes cannot be two, three or four.

Writing possibilities in small numbers does mean that it ends up as rather a big mess. I do it all in pencil. Once I’m sure, then I write the answer in pen and rub out the pencil marks.

If you go across and you are filling in all the possibilities in all the rows, you might look down the columns and see something really obvious.

I always start with the figure one and work my way through to nine, but some people glance at the grid first to see if there are already a lot of a particular number and start with that.

If the puzzle is made properly, you should be able to solve it all using logic, but if you are in a competition, then it can save time to make a guess.

Sometimes you get a mental block and you cannot see what you should do. Making a guess is a feasible way of doing it. It just means that if you get it wrong you have to go back and start again.

Most people use the same technique as I use, but I am very fast.

Explore Games & Puzzles

• Crossword

• Linkudo

• Sudoku

• Killer Sudoku

• Chess

• Bridge

• Crickler