Pips September 16, 2025

Hints and answers for September 16, 2025

Stuck? Take it in stages. A nudge costs less than the full answer, and the answer is here if you want it — each diagram below is the verified solution our generator built this board from, using tiles drawn from the standard double-six domino set. On the looser boards other valid arrangements can exist too; any filling that covers every square and satisfies every region counts as solved.

What's on these boards

The difficulty ladder

These are three separate boards, not one board with hints removed, so playing all three on September 16, 2025 gives you three genuine attempts rather than three views of the same solution.

easy

8 squares, 4 dominoes, 3 regions, 2 region boundaries. 33% of its regions carry something other than an exact total, and the widest region spans 3 squares.

medium

14 squares, 7 dominoes, 5 regions, 6 region boundaries. 40% of its regions carry something other than an exact total, and the widest region spans 4 squares.

hard

20 squares, 10 dominoes, 7 regions, 10 region boundaries. 43% of its regions carry something other than an exact total, and the widest region spans 4 squares.

Where this puzzle comes from

This board was not hand-designed and it was not copied from anywhere. The generator laid down a valid arrangement of 10 dominoes first, then divided the 20 squares into 7 regions and derived each region's rule from the values that had already landed in it. Because the solution existed before the constraints did, this board provably has one.

It was then loosened: rules were swapped for weaker ones, one at a time, keeping each swap only while the number of valid arrangements stayed inside the bound for this difficulty. That is why 3 of the hard board's 7 regions carry something other than an exact total.

Generation is seeded from the date, so September 16, 2025 produces this exact board on every device, permanently. Sharing this link always shows the same puzzle. More on the process in our editorial policy.

What goes wrong on this one

The all-different region is the one to watch. With 4 squares in the widest region on this board, an all-different rule quietly forbids far more arrangements than it looks like it does.

The all-different region is the one to watch. With 4 squares in the widest region on this board, an all-different rule quietly forbids far more arrangements than it looks like it does.

If you have genuinely stalled, undo back to the last tile you were confident about rather than reshuffling everything. Most dead ends on a board this size trace to one early placement made on a guess, and everything after it inherits the mistake.

Boundaries, not regions

There are 10 distinct region-to-region boundaries on this board, which is a lot for 7 regions. Almost every tile you place is going to land half in one region and half in another, so treating regions as separate sub-puzzles will not work here — think in pairs.

A domino can straddle two regions, and each half only has to satisfy the region it lands in. That is the single most common misreading of the format — people assume a tile must sit inside one region, which makes perfectly solvable boards look impossible. The rules page works through it with examples.

What your tray forces

The tray holds 4 doubles (0-0, 2-2, 3-3, 4-4), and the board has 2 regions governed by an equality rule. A double can never sit entirely inside an all-different region, so those tiles have to straddle a boundary — which usually pins them down before anything else on the board.

The heaviest tile on the hard board is the 4-6 and the lightest is the 0-0. Those two are worth locating first: the heavy tile can only go where a sum has room, and the light one is often the only thing that fits a tight region.

Reading the outline

The shape fills about 83% of its 6×4 bounding box, so there are a few notches in the outline. Squares along those notches have fewer neighbours than they look like they do — check them before you commit tiles elsewhere.

The easy board is a different animal: this is a distinctly irregular outline, filling only 67% of its 4×3 bounding box. Narrow arms are the danger: a square at the end of a one-wide corridor has exactly one possible partner, so if that partner gets covered the board becomes unsolvable regardless of what else you do.

The badges on this board

The hard board uses 3 of the six possible region rules. What each one is actually demanding here:

= 9

Spreads exactly 9 pips over 2 squares, an average of 4.5 each. Anything that pushes the running total past 9 is already lost, so this is the region to count before you commit.

≠

Forbids any repeat across its 4 squares. Note that this constrains values, not tiles — two different dominoes both contributing a 4 still breaks it.

> 0

Requires every value above 0, leaving only 6 of the seven pip values legal in those 4 squares.

The full badge vocabulary, including the ones this board happens not to use, is on the pips rules page.