Crown Grid: Logic Puzzle

How to play Crown Grid

The board is a square grid cut into colored regions. You place crowns by logic.

The rules

• A board is N×N, from 6×6 to 10×10, with N colors. Each color is one connected block of cells.
• Put exactly one crown in each row, column and color.
• No two crowns may touch, even at a corner.
• You win when N crowns stand with no clash. Crosses and dots are notes only.

A crown rules out the rest of its row, column and color, plus the eight cells around it.

Controls

• Tap or click: a blank cell gets a ×, a second tap gets a crown, a third clears it. A right-click toggles a ×.
• Drag: across blank cells to cross several at once, or start on a × to erase ×s. One Undo reverses the whole drag.
• Keyboard: Tab to the board, arrows to move, Space or Enter to tap, X for a ×, C for a crown, Z to undo, Y to redo, H for a hint. Press H again to carry the hint out.
• Auto-X: on by default, in the More options menu. A crown puts dots on every blank cell it rules out. Removing a crown clears only the dots that no other crown rules out.
• Clock: it starts at your first move or hint and pauses when you leave the tab.

Clashes and hints

• Clash: both crowns turn red, and the row, column or color they share is striped (for touching crowns, just their two cells). The message area says why. Each clashing crown you place adds a mistake. There is no losing state.
• No room left: a row, column or color with no crown and no open cell is striped, with a note that one of your marks is wrong. An open cell is a blank one that no crown rules out.
• Hint: it first checks your marks for a clash, a row, column or color with no room, or a crown or × that contradicts the answer. With Auto-X off, it next offers to cross out the cells a crown rules out. Then it names the next logic step and lights the cells involved. Show me carries the step out. Each hint you open adds one to Hints on the result card.

Tips and strategy

These are the steps our solver uses. The hint names them the same way.

1. Start with the small colors. A color, row or column that still needs a crown and has one open cell takes it there. The hint calls this Last cell.
2. Find a color stuck in one line. If all open cells of a color lie in one row, its crown is in that row, so cross out the rest of the row. The reverse works too: if a row’s open cells all share one color, that color’s cells outside the row are out. This is Confinement.

3. Test a cell with an imaginary crown. If a crown there would leave a row, column or color with no open cell, cross the cell out. This is Sees all.
4. On Hard, compare groups. If two colors have all their open cells in just two rows, those rows’ crowns belong to those colors, so other colors lose their cells there. Columns work the same way, and so do groups of three or four. The hint calls these Pairs and Groups.

Our numbers

These numbers come from the game’s test records, scripts and code; How we test covers the method behind each check.

Before the colors. With one crown in each row and column and none touching, the placements grow fast. The colors must cut them down to one.

Counts from OEIS A002464, Hertzsprung’s problem (n non-attacking kings on an n×n board, one in each row and column), checked 2 November 2026.

Checks on the boards you play

• Daily table, 25 October 2026: it holds 1,127 boards, from 1 October 2026 to 31 October 2029. A separately written counting program found exactly one answer for each, and each board was solved by the logic steps from an empty board at its listed level, matched the generator and had no repeat. 0 failures. The table, generator and rules were the same on 27 October.
• Free play, 25 October 2026: 4,500 boards, 300 for each of the 15 size and level combinations. Each had exactly one answer, a logic solve and its level. 0 failures.
• Hint advice, 25 October 2026: 1,999 partly filled boards with correct marks. The hint gave 0 wrong crowns or crosses.
• Hint sentences, 27 October 2026: all 1,127 Daily boards replayed, 18,175 steps and 31,636 target cells. 0 failures in checking the cells and the rows, columns, colors and counts each sentence names.

Time to build one board (in our test suite: browser test, processor slowed 4×, 200 boards per cell, median in milliseconds)

In that test the slowest 10×10 Hard board took 4.9 seconds. The Daily comes from a prebuilt table, and Free play prepares the next board in the background. With nothing prepared and the processor slowed 4×, a first 10×10 Hard board can show “Setting up the board…” for up to about 5 seconds.

Daily puzzle and records

A date’s board comes from the date alone, so everyone whose device shows that date gets the same one. A new board starts at midnight, your time. Size and level follow the weekday:

• The mix: the table’s 1,127 days make 161 weeks, so this schedule gives 322 Easy, 644 Medium and 161 Hard boards. Daily Easy boards are built to need at least one Confinement step.
• One counted try: your first finished Daily of a date counts. Replay as practice reruns that board and changes no stats.
• Records: Played, a Best for each size and level, and one streak and longest streak across all weekdays. The result card adds mistakes, hints and the logic our solver needs for the board, such as “Last cell · Confinement — 8 logic steps”.
• Free play: each of the 15 size and level combinations keeps its own Best.

The Daily boards of our other games are on the Daily page.

Frequently asked questions

Do I ever have to guess in Crown Grid?

No. The generator keeps a board only if our logic solver can finish it from an empty grid, and a board that logic can finish has one answer. If you are stuck, Hint looks for the next logic step.

How are Easy, Medium and Hard decided?

By the hardest step our solver needs, not by board size. Easy needs only Last cell and Confinement. Medium needs Sees all at least once. Hard needs Pairs or Groups at least once, and each color has two or more cells.

Do hints change my time or Best?

No. Best compares finishing times only, so hints leave it alone. A solve with no mistakes and no hints earns the note “Clean solve — no mistakes, no hints”.

How big are the cells of a 10×10 board on a phone?

On 27 October 2026 we measured 28.8 px on a 320 px wide screen, 32.8 px at 360, 35.8 px at 390 and 52 px at 1280. In the checks of 26 and 27 October, buttons and menu items measured at least 44×44 px.

Last updated: November 2, 2026.