Practise: W-Wing
This puzzle is picked so that the easy moves run out and exactly the W-Wing gets you going again. Solve as far as you can — when nothing obvious is left, the pattern is waiting for you.
Skip the obvious cells and start right where the technique is needed.
How to spot it
Find two cells with identical pairs of candidates in different units. Then look for a row, column or box where one of their two digits has exactly two candidates, positioned so that each sees one of the pair. The other digit is what you eliminate from cells seeing both.
Put it to use
Where you will meet it
Expert grids are the only place this pattern regularly decides the solve. Bring your notes.
Play ExpertStuck on a grid of your own?
Type the position into the solver and it walks the whole solution, naming the technique behind every step — including this one.
Open the solverPrefer paper? Ready-made Expert sets as a PDF.Print puzzles