12×12 Queens puzzles — unlimited practice

A fresh 12×12 board whenever you want one, at any difficulty, with 241 finished 12×12 boards behind this page. It is the largest board on the site: twelve queens, twelve colours, a hundred and forty-four squares. Place 12 queens: one in every row, one in every column, one in every colour, and no two touching — corners included. Change the difficulty with the pill beside the board, switch size from the Unlimited tab, and keep going: no daily limit, no streak to protect, no clock you have to beat.

What a 12×12 Queens board asks of you

A 12×12 is a test of discipline more than of insight. Every technique it can ask for was already available on a 6×6; what is new is holding a dozen partial conclusions at once without dropping one of them. The board rewards patience and punishes exactly one thing, which is trusting your memory over your marks.

Which technique opens the board is what the difficulty pill beside it really changes. The strategy guide works through each named technique in the order the solver reaches for them, and the hint button on this board names the same ones.

Difficulty at 12×12 is a claim about the reasoning

The label never describes the square count — every board on this page has the same 144 squares. It describes what a board demands before it gives up its first queen, and the two move independently: a 12×12 rated beginner can be a shorter read than a 5×5 rated hard, 119 extra squares and all. The Queens Unlimited hub makes the same case with two real boards side by side.

• Beginner — 20 boards. One region already holds a single square, so the first queen is free and the rest falls to counting rows, columns and colours. That one gift is deliberate: from an empty grid the simplest techniques have nothing to bite on without it.
• Easy — 95 boards. Opens on a colour confined to one row or column. It owns that line, everything else in the line is dead, and the 12×12 comes apart from there.
• Medium — 98 boards. Several of those confinements chained together, each one visible only after the last has been marked off — which across 144 squares means marking is part of the technique, not tidying up after it.
• Hard — 28 boards. Pigeonhole arguments spanning several of the 12 regions at once, plus the exclusion reasoning that rules a square out by showing what it would break.

Beginner or easy. A 12×12 rated beginner is the gentlest way to find out whether the size is the problem or the reasoning is — it is the same board the hub uses to show that difficulty and size are different axes.

Practising at 12×12

Work in regions, not in rows. On a grid this wide it is far easier to keep track of "which colours are still open" — twelve things — than of every square you have looked at, and the colour count is the thing that ends the board anyway.

Two things hold at every size. A hint never guesses: it finds the next move a person could justify, names the technique, and waits for you to press show me before it marks anything. And boredom means move up a difficulty, not a size — the same reasoning with more squares around it is not new practice. The hub page has the full method.

Every 12×12 board here is provably fair

Each one was checked twice: once for having exactly one solution, and once for being reachable from an empty grid without a single guess. The check reruns over the whole pool before every release, so it covers all 241 12×12 boards rather than the handful anybody happened to play. If you are stuck here, there is a next step and the hint can name it.

Where 12×12 sits

Nothing on the calendar comes near 12×12; the Daily Max stops at 10×10.

• Daily Mini — three boards a day, 6×6 to 8×8. The one that carries a streak.
• Daily Max — ten boards a day, climbing to 10×10 and finishing harder than the Mini ever gets.
• Archive — every past day, still playable and still scored the same way.
• 11×11 practice — one step down, if 12×12 is currently more search than reasoning.

Every Queens board size

• 5×5
• 6×6
• 7×7
• 8×8
• 9×9
• 10×10
• 11×11
• 12×12