Practise: Hidden Quad
Look only at the highlighted row or column. Which four digits have only these four homes?
The four prepared note cells sit in the highlighted unit. Do not place a digit yet: first find the four digits that can only go here.
Example 1 of 4
Your turn first
Which four digits belong only here?
Look only at the four prepared note cells in the highlighted unit. Which four digits occur only in these cells? Do not place a digit yet; find the quad first.
Remember
A Hidden Quad is simple: if four digits can each go only in the same four cells, every other note in those cells disappears. The order of the four digits is not fixed yet.
Put it to use
Where you will meet it
Expert grids are the only place this pattern regularly decides the solve. Bring your notes.
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