Use the two-row trick
Each pair of rows holds two boxes, side by side. A digit appears once in each box and once in each row. So if a digit is in the top row of the left-hand box, it must be in the bottom row of the right-hand box, and the other way round.
That one look cuts a box from six cells to three, and often to one. In this position, the 5 in row 3 sits in the left-hand box. The 5 in the right-hand box must be in row 4, and row 4 has only one empty cell there.
Nothing like this exists on the nine-by-nine grid, where a digit in one box leaves two rows open in the next. Check it for every digit as you scan.
Finish anything that is nearly full
A line of six cells with four filled is missing just two digits. Name them, then check one of the two empty cells. If its column or box already has one of the digits, both cells are solved at once.
Row 5 of this position is missing 2 and 4. The empty cell in column 2 can’t be 4, because column 2 has one. So that cell is 2 and the cell at the end of the row is 4.
Do this first, before any scanning. Two placements for one look is the best rate you will get.
Leave the notes off
Notes cost time. Writing them takes several taps a cell, and the daily puzzle can be finished with singles, which need none. Solve in your head. This is the opposite of the advice for the nine-by-nine grid, where notes are how you find pairs.
If you do get stuck, don’t fill in the whole board. Note the two candidates in the one or two cells you are unsure about, and carry on.
Scan in a fixed order
Hesitating over what to check next costs more than any single check. Pick a routine and keep to it: nearly full lines first, then digits 1 to 6 in order, each across the three pairs of rows from top to bottom.
When a digit is complete, drop it from the routine. On LarkSpark the number pad shows a tick on a digit once all six copies are placed, so you can see at a glance which digits are left.
After a placement, look at that cell’s row, column and box before going back to the routine. On a grid this small, one placement nearly always opens another next to it.
Keep your hands still
On a computer, use the keyboard. The arrow keys move between cells, the keys 1 to 6 enter a digit, Backspace or Delete clears a cell, and N switches notes on and off.
On a phone, select the cell first and then tap the digit. Work across one pair of rows at a time, so your thumb isn’t crossing the board between entries.
Where the time goes
- Wrong entries. A repeated digit turns red, but the board doesn’t say which entry was the mistake, and finding it can cost more than the rest of the solve. Check the digit against its row, column and box before you enter it.
- Guessing. With two candidates left it is tempting to try one. A wrong guess costs far more than the few seconds it takes to find the real answer.
- Looking at the clock. It doesn’t help.
For the logic behind each of these moves, see techniques on a six-by-six grid. For the general method, the solving tips walk through it step by step.