Fast solvers are not doing harder reasoning at higher speed. They are doing the same reasoning with far less searching in between. Almost all of the improvement is in what you look at and in what order.
1. Retire digits as you finish them
Once a digit appears nine times it is done, and any time spent scanning for it afterwards is wasted. The number pad here dims completed digits, so the information is already on screen — use it to narrow which digits you sweep for.
2. Scan in a fixed order
Always sweep digits in the same sequence, and always visit boxes in the same order within a sweep. A fixed route means you never wonder whether you have already checked something, which is where a surprising amount of time goes.
3. Use bands and stacks
Look at three boxes in a horizontal band at once. If a digit is already placed in two of the three, the third is heavily constrained — often to a single row, sometimes to a single cell. Band scanning finds placements that single-box scanning misses entirely, and it costs no extra effort.
4. Count gaps, not cells
A row with only two empty cells is nearly always resolvable in one look. So is a box with two gaps. Scanning for nearly-full regions is a faster entry point than scanning for a digit, especially in the middle stage of a puzzle.
The two-gap sweep
Every few placements, run your eye across all rows, columns and boxes looking only for regions with two empty cells. It takes seconds and frequently produces two or three immediate placements.
5. Delay notes as long as possible
Filling candidates takes time and creates visual noise that slows every subsequent look. On easy and medium puzzles, scanning alone will finish the grid, and starting with notes can double your solve time.
The signal to switch is objective: a complete sweep of all nine digits with zero placements. Before that, keep scanning.
6. Use the highlighting deliberately
Selecting a cell here highlights its row, column and box, and every cell sharing its digit. That second part is the useful one for speed — click any 8 and all the other 8s light up, which turns a scan into a glance.
A fast routine: click an instance of the digit you are sweeping, look at which boxes are unlit, and check those.
Accuracy is part of speed
A wrong digit costs far more than a slow one. Unwinding a contradiction can take longer than the entire rest of the puzzle, so anything that trades accuracy for pace is a bad deal. Speed should come from cutting search time, never from loosening the standard for placing a digit.
Measuring progress
Best times are recorded per difficulty on this device, so you can see improvement on comparable puzzles. Compare like with like — an easy grid and an expert grid are not the same task — and expect improvement to plateau and then step down rather than falling smoothly.
| Level | Comfortable pace | Quick |
|---|---|---|
| Easy | 4–6 min | under 3 min |
| Medium | 7–12 min | under 6 min |
| Hard | 12–20 min | under 10 min |
| Expert | 20–35 min | under 15 min |
These are rough bands for solvers who are comfortable with the techniques, not targets. Solving accurately at any pace beats solving quickly and restarting.