Yes, a legal match in Number Match 10 can absolutely cause a deadlock — meaning you make a perfectly valid move that sums to 10 across orthogonally adjacent cells, yet afterward no legal pair remains on the board and you are stuck. The deadlock is not a bug; it is the natural consequence of the game's no-gravity, fixed-position rule combined with the order in which you remove your three matching pairs. On the fixed six-cell board with values 1, 9, 1 in the top row and 9, 2, 8 in the bottom row, four legal pairs exist at the start, and the three non-overlapping pairs can be cleared in any order to finish the puzzle. One tempting order — removing the top-left horizontal 1+9 first and the bottom horizontal 2+8 second — instead leaves the last 1 and 9 stranded on a diagonal where they sum to 10 but are not orthogonally adjacent. Because diagonal cells are never legal partners in Number Match 10, the browser detects the stranded pair, displays a Restart prompt, and waits for you to retry. Understanding this trap is the entire point of the game, and it is what separates Number Match 10 from a make-10 exercise with no real choice.
Why a Legal Pair Can Strand the Board
Number Match 10 is built around one transparent product rule: you select two orthogonally adjacent numbers whose sum is exactly 10, and that pair disappears. The board is fixed — two rows and three columns — and removed cells stay empty instead of collapsing or applying gravity. That preserved geometry is what makes a deadlock possible. When you remove one pair, the only adjacencies that change are the cells you already cleared; the remaining numbers keep their original positions, so a pair that was legal at the start can become unreachable if an empty cell ends up between two viable partners.
The starting layout reads like this when you face the puzzle:
| Row | Column 1 | Column 2 | Column 3 |
|---|---|---|---|
| Top | 1 | 9 | 1 |
| Bottom | 9 | 2 | 8 |
Four legal pairs exist at the start: the vertical 1+9 in the left column (cells 0 and 3), the top-left horizontal 1+9 (cells 0 and 1), the top-right horizontal 9+1 (cells 1 and 2), and the bottom horizontal 2+8 (cells 4 and 5). The diagonal 1 and 9 in cells 2 and 3 sum to 10 but are not legal because they share only a corner, not an edge. Every move you make narrows that list, and the order in which you remove the three real pairs determines whether the final number on the board still has a partner.
To play Number Match 10, you move a visible cursor across the grid with the arrow keys, press Space or Enter to lock in the first number, then move to an adjacent cell and press again. If the second cell is orthogonally adjacent and the values total 10, both numbers vanish and your score climbs by 100. If either condition fails, nothing disappears; the newer cell becomes the next first selection. Pressing the same square twice cancels it. Removed squares cannot be selected again, and no number of diagonal tricks will substitute for a real shared edge.
The Winning Route: Clear All Six Numbers for 300 Points
This is the complete route that clears the board without trapping a single number. Follow each step in order.
- Use the arrow keys to place the cursor on the top-left 1 (cell 0) and press Space or Enter to select it.
- Arrow down to the bottom-left 9 (cell 3) and press Space or Enter. The values 1 and 9 are orthogonally adjacent and sum to 10, so both cells disappear and the score rises by 100.
- Arrow up to the top-middle 9 (cell 1), press Space or Enter to select it, then arrow right to the top-right 1 (cell 2) and press Space or Enter. The second horizontal pair vanishes for another 100 points.
- Arrow down to the bottom-middle 2 (cell 4), press Space or Enter to select it, then arrow right to the bottom-right 8 (cell 5) and press Space or Enter. The final pair clears and adds the last 100 points.
All six cells are gone and the score reads 300. Because the top-left horizontal 1+9 (cells 0 and 1) was never used, the bottom-left 9 stayed available as the vertical partner, which is what keeps the board solvable at every step. This is the winning route the puzzle's logic layer guarantees, and it is the route the puzzle's own automated fixture proves end-to-end.
The Deadlock Trap: A Legal Order That Strands the Final Pair
The trap looks innocent. You start by selecting the top-left 1 and the top-middle 9 — a perfectly legal horizontal pair that sums to 10. Both cells vanish. You then feel clever and remove the bottom-middle 2 and the bottom-right 8 — another legal horizontal pair that also sums to 10. Your score shows 200 and four cells are gone. What remains is the bottom-left 9 and the top-right 1.
Those two remaining numbers still add to 10, so the casual assumption is that one more move wins the game. But the bottom-left 9 sits in column 1 and the top-right 1 sits in column 3, with the empty middle column between them. They share a diagonal corner but not a horizontal or vertical edge, so the orthogonal-adjacency rule rejects them. With no legal pair on the board and two numbers still standing, Number Match 10 declares a deadlock and prompts you to Restart.
The single demonstrated deadlock sequence — top-left horizontal 1+9 first, bottom horizontal 2+8 second — strands the last two numbers on a diagonal. That is exactly why the puzzle designer chose those two specific removals as the deadlock demonstration.
How Number Match 10 Detects and Reports the Deadlock
Detection happens in the game's pure logic layer. After every removal, the engine enumerates every pair of remaining cells, requires a Manhattan distance of exactly one, and then checks that the pair sums to 10. If at least one such pair exists, the game continues. If no pair exists but cells remain, the engine flags a deadlock and prompts you to Restart. If no cells remain, the engine records a completion at 300 points. The same routine also rejects selections on already-removed indices, on non-adjacent cells, and on pairs whose values do not total 10, so a deadlock is simply the state where at least one number remains but the legal-pair list is empty.
The browser never lets the deadlock sit unresolved. The Restart action restores all six numbers, clears the selection, returns the cursor to the first cell, and resets the score to zero. A best-score record may be kept in localStorage on the same machine, but it is not transmitted. Double-pressing Escape opens a shared simulated spreadsheet screen that doubles as a boss key; pressing Escape twice again returns you to the puzzle. There is no canvas, no random generator, no timer, no audio, and no account or download. Every keyboard press is deterministic, and the deadlock prompt is the only way the game asks you to start over.
Practice the Trap Until the Winning Route Feels Automatic
Because Number Match 10 has exactly four legal pairs and the deadlock trap is reachable, the fastest way to internalize the deadlock is to trigger the trap on purpose. Remove the top-left 1 and top-middle 9, then remove the bottom-middle 2 and bottom-right 8, watch the Restart prompt appear, and confirm visually that the remaining 9 and 1 sit on a diagonal. Restart, then play the winning route and see the 300-point board clear. Repeating both sequences a few times turns the rule from something you read into something your fingers know.
The same discipline applies to the score formula: each successful adjacent pair is worth 100 points, so a partial clear that strands two cells in the wrong place leaves you at 200 instead of 300. The board never collapses and never applies gravity, so the only variable is which of the four legal pairs you spend first. Other short logic games on Lizely use similar fixed-route mechanics, so the same deliberate approach transfers to puzzles such as Mosaic, LITS, Thermometers, and Battleships if you want to keep practicing the feel of a small route-choice board with a single sharp trap.