How to Start a Hard Case

An easy case usually lets you place someone within the first few minutes. A hard one is built not to. In the casebook, the median hard case takes twelve deduction steps before a single suspect can be placed for certain, and the toughest holds out for twenty-six. For all that time nothing is settled, and the board can look exactly as open as when you started. That is where most people give up, and it is almost never because they missed something obvious.

What gets you through is not a trick but a routine: a fixed order in which to look at the case, so that the first ten minutes always produce something, even if that something is only a list of tiles crossed out.

1. Read Every Clue Before Touching the Board

It is tempting to start with the first suspect and work down the list. Resist it. On a hard case the clue that pins down Anna is very often written under someone else’s name — “north of Anna”, “in the same room as Anna”, “beside the same table as Anna”. Read the whole file once, including the clues about the whole scene, and note which suspects are mentioned in other people’s clues. Those are the ones the case is built around.

2. Count, Then Order

For each suspect, work out roughly how many tiles their own clues allow. You do not need exact numbers; “three”, “about ten” and “most of the board” are enough. Then work in that order, shortest list first. A suspect with three possible tiles is where any elimination does the most damage, and a suspect whose clue only relates them to someone else will not move until that someone else does.

Use the pencil notes for the short lists. A tap leaves a note on a tile without placing anyone, and marking the three possible tiles of your most constrained suspect makes the next elimination visible the moment it happens.

3. Look at the Lines

Before going any deeper into clues, sweep the board for structure. Which rows or columns have only one or two open tiles because furniture blocks the rest? Which of your short-list suspects share the same two rows? Hard cases are usually opened by line reasoning rather than by a clue — a pair of suspects locked into two columns, or a row with a single free tile that takes a column with it. The guide articles on locked lines and on the one free tile describe both.

4. Then the Rooms

If the lines give nothing, turn to rooms. Small rooms are the most valuable: a box room two tiles wide can hold at most two people, and only diagonally. Ask, for each clue about company — alone, with a man, with someone wearing glasses — which rooms could possibly satisfy it. Clues about the whole scene belong here too: “no room was empty” on a plan with as many rooms as suspects means every room gets exactly one suspect, which is a very strong statement once you see it.

5. Go Round Again

One pass of the routine rarely places anyone on a hard case. It crosses tiles out. The point is that it always crosses something out, and that every crossed tile is a reason to go round again — first the short lists, then the lines, then the rooms. The first placement, when it comes, usually triggers several more in quick succession, because a placement clears a whole row and column at once.

And when you are truly stuck, the hint giver in the game explains the next step the solver would take, in a sentence, without placing anyone for you. Using it once is not cheating; it is how the routine gets learned.

Hard Cases That Hold Out Longest

The hard cases in the casebook where the first placement comes latest — the ones this routine is for:

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The Techniques

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