This method extends the idea of a Hidden Singles. Consider a house (row, column or square) where two
candidates are only seen in two of the cells. Then it is certain that both candidates will be
placed in these two cells, but we do not know in which order. In any case, no other candidates
can be in the two cells and we can eliminate them.
In this example consider row G. The cells G5 and G6 are the only ones in the row which contain both 3 and 6. Hence we know that {3, 6} will be in these two cells in some order, but no other candidates can be in these cells. Hence, we can eliminate all other candidates in these two cells.
As with all basic methods, we can look for a Hidden Pair in rows, columns and squares. In the example below we see a Hidden Pair consisting of candidates {3, 8} in the bottom-right square. Both 3 and 8 are only seen twice in the square, namely in G8 and I7. Therefore, these two cells will surely contain both candidates and we can eliminate 1 and 7 from I7.
Hey there and welcome to our Learn Section!
If you are new to our website, please check out the How To Play section. It will introduce you to
the various tools and options used in our Web Platform. The section also contains interesting articles on
grading and generating our sudoku boards.
We are ordering our boards into the following difficulties - Very Easy, Easy, Medium, Hard,
Extreme and Impossible. The first three include the most basic strategies, which are a good point
for Sudoku Beginners to start at.
The last three include, among others, various Wings, Colourings and -Fish strategies which are often used by
advanced Sudoku players.
One great feature in our website is our Solver which can be used to Learn Sudoku on the go.
If you are stuck on a Hard Sudoku board, you can use the solver to grade it and show
you a step-by-step solution. The "Load in Solver" option is very useful and available for every example in our
Learn section.
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Happy learning! :)