X-Wing Basics
A classic advanced pattern that makes expert puzzles feel approachable.
The X-Wing sounds intimidating but is a tidy, visual pattern once you know what to look for.
The pattern
Choose a digit. Find two rows where that digit can only appear in exactly two cells, and those cells line up in the same two columns. The four cells form the corners of a rectangle.
Why it works
In each row the digit must take one of its two corners. Whichever way it falls, the digit ends up once in each of the two columns. So you can remove that digit from every other cell in those two columns.
Practice
Try an Expert puzzle in Quietgrid with notes on. When you feel stuck, pick one digit and check rows for exactly-two placements.