Tools for 6x6 Hard puzzles, when the easy deductions run out.
A 6x6 Hard puzzle has 36 squares per category row and often 25 or more clues, many of them comparing three items at once. The basic moves (cross off what a clue rules out, place an item when one option is left) still do most of the work, but sooner or later you'll reach a point where no single clue gives you anything new. This guide covers the techniques that get you past that point, roughly in the order you should try them.
Before reaching for anything fancy, make sure you've done a full location scan. For each category, go across the six locations and ask: “Which items can still go here?” If the answer is one, place it. In the step-by-step walkthroughs in our archive, these show up as “The Lake still needs one of the dogs, and only one of them can go there.” They are the single most commonly missed deduction in hard puzzles, because nothing in the clue list points you at them.
“Same location” clues glue two items together. In a hard puzzle you may have three or four of these, and they can chain: if the donut is with the pepper, and the pepper is with the clarinet, then all three share a location. Treat the group as one unit. Every location ruled out for any member is ruled out for all of them.
Linked groups make other clues much stronger. Say the donut is linked to the pepper and you know “the pepper patch is not next to the akita”. If you then learn where the donut is, you can immediately cross off two squares for the akita, even though no clue mentions both the donut and the akita.
If two items in the same category both have exactly the same two possible locations, say the Beach or the Snow, then between them they must fill both. You don't know which is which yet, but you do know that no other item in that category can be at the Beach or the Snow. Cross those squares off everywhere else in the row.
The same idea scales up: three items whose options all fall within the same three locations lock those three locations. Locked groups are easy to overlook because none of the items is placed, but they often unlock the next placement in the same category.
A single “left of” clue is weak. Two or three that share an item are strong. Suppose:
Together these form a chain, fries → retriever → hockey, with the hockey game at the Snow at most. The retriever is then at the Lake at most, and the fries at the Trail at most. Writing the chain out turns three weak clues into a band of eliminations. Look for any item that appears in two or more relative clues and combine them.
Equidistant, closer-to, and farther-than clues are almost useless at the start of a puzzle, but they're excellent filters at the end. When an item is down to two or three candidate locations, test each candidate against every three-item clue it appears in. Equidistant clues are particularly strict: the outer two items must be an even number of locations apart, so if they're both partly placed, only a handful of combinations survive.
Occasionally even an expert-level scan finds nothing. Then you can use a contradiction test: pick an item with only two possible locations, assume it's at one of them, and follow the consequences. If that assumption leads to something impossible, such as an item with no locations left or two dogs at the same spot, the assumption was wrong, and the item must be at the other location.
This is not guessing. A guess commits to an answer and hopes. A contradiction test proves an answer by showing the alternative is impossible. A few habits make it reliable:
The archive walkthroughs show these tests as “Suppose the Golden Retriever were at the Snow...”. Fewer than one in twenty daily puzzles needs one, and when it does, it's usually a single test near the middle of a 6x6 Hard.
Want to see these techniques in action? Every archived daily puzzle has a full walkthrough. Try spotting the linked pairs and chains in a 6x6 Hard solution before reading each step. If any clue wording is unclear, the clue types guide explains each one.