Expert
Follow it to a contradiction
Assume a cell, follow the logic, and cross it out when it breaks.
When every other technique is spent, pick a suspect with two open cells and assume one of them. Follow the easy techniques from there. If that leads to a rule broken, such as a row nobody can fill or a victim with no companion, the assumption was wrong: cross that cell out and the other one is the answer.
This is not guessing. You only keep a result you have proved. Use notes for the trial so you can erase it cleanly, and try the suspect with the fewest cells first.
Choose where to start
Pick a suspect with exactly two open cells. A cell that would fill a crowded row or column, or put someone in the victim's room, tends to break something quickly, and a short chain is easier to check than a long one.
Follow it with the easy techniques
From the assumed cell, cross out its row and column, then apply pinned suspects, only one fits and room counting. Stop as soon as something is impossible: a suspect with no cell left, a row nobody can reach, or a victim's room with no companion or two. That proves the starting cell was wrong.
If the chain runs out without breaking anything, you have not proved anything yet. Erase the trial notes and try the other cell, or a different suspect.
Why it still counts as logic
Every case has exactly one solution, so a cell that leads to a broken rule cannot be part of it. The only thing you keep from a trial is the fact that the cell is impossible, which you have proved. The trial notes go back to the eraser. Expert cases, the daily on Saturday, are the ones that need this step.
The diagram, step by step
In the diagram above, Rafael has two open cells. If he stood on the left one, the second column would have nobody left who could stand in it, and every column must hold one person. So the left cell is crossed out, and Rafael takes the other one.
Practice case: Expert 6×6
This case needs the technique above. Try it before you read the next tip.
She was beside a stool.
Pick a suspect, then tap a cell.
Play this case and the whole casebook in the app, free on iPhone, iPad and Android.
