Practise: Naked Quad
Look only at the highlighted row or column. Which four squares together use just four small digits?
The prepared notes are all in one highlighted unit. Find the four squares that together use only four digits; do not place a digit yet.
Example 1 of 4
Your turn first
Which four squares belong together?
Look only at the prepared notes in the highlighted unit. Which four squares together contain only 2/3/5/9? Then identify which of those notes disappear elsewhere.
Remember
A Naked Quad is simple: four squares use only four digits between them, so those digits disappear from every other square in that unit. The quad does not set their order yet.
Put it to use
Where you will meet it
Hard grids are built around moves like this one. That is where it earns its keep.
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