The ultimate Swudoku strategy guide for new players

If you already know the tap-tap-swap basics, skip the rulebook and use this as a tactics sheet. If you don’t, read how to play first, or the short Swap Sudoku definition, then come back.

Score = how many swaps you used. Lower is better. There is no timer, so rushing only makes the number worse.

Read the board before you touch it

The grid starts full. Your first job is not to swap. Spend half a minute finding the ugly stuff: two 7s in one row, a number that obviously belongs in the block next door, a cell that’s grey for a reason you can already name.

Players who tap first and think later spend swaps putting tiles back. The cheap scores come from people who can already see two or three good moves before the first tap.

Let the colours do the navigating

You don’t need to memorise a lecture. You need a map.

• Grey: wrong cell. These are the only tiles that must move.
• Yellow: right cell, but the row, column, and 3×3 block are all still unfinished. Leave it. Fix its neighbours.
• Green: right cell, and any one of row / column / block is complete.
• Dark green: right cell, and all three groups are complete.

Yellow, green, and dark green are already home. Swapping them “just to see” is how you invent extra work. When the whole board is dark green, you’re done.

Hunt Double Swaps on purpose

A Double Swap is the good one: two tiles, one move, both land in the correct cell. It’s worth pausing for. Scan two greys and ask whether they simply want each other’s seats.

If only one of them would be happy, you’re paying a swap to create a new problem. Sometimes that’s necessary. Often it isn’t. The low scores are mostly people who refuse to spend a move unless it solves something.

Finish a block, then follow the mess

A completed 3×3 lights those tiles green (or dark green, if the rows and columns are already done too). The rest of the board gets easier to read because a chunk of it stops shouting.

Don’t hop around the whole 9×9. Untangle one block, watch which greys are left, then take the adjacent row or column that just became obvious. Random swaps across the grid feel busy and score badly.

Undo is free. Use it.

Undo reverses the last swap. It does not punish you. If the colours get worse, wind it back and try the other pair you were considering.

New players treat undo like cheating. Undo is how you test a line without donating five swaps to a hunch.

A simple order of operations

1. Scan. Don’t tap.
2. Mark the Double Swaps you can already see. Do it in your head. There isn’t a pencil.
3. Clear a block that’s close to done.
4. Recheck colours. Only grey tiles need to move.
5. Slow down when a handful of greys remain. The last few swaps are where sloppy boards bleed points.

After you finish, you can share the result. If you’re signed in, you may also get a How you compare histogram of swap counts for that puzzle. Same account on the web and in the iOS app syncs game stats both ways.

Go try it on today’s board

Tactics only stick if you use them on a live grid. Play today’s Swudoku and see whether reading first actually drops the swap count.

Stuck on a colour or a scoring quirk? The FAQs have the short version.