Custom puzzles

Type in a puzzle from a magazine, a book or another app, and use every Grid9 tool on it: notes, Fill auto, the hint ladder and the technique explanations.

Premium. Entering your own puzzle is a Premium feature. Everything you do on it afterwards works exactly as on a built-in puzzle.

Step 1 Premium

When it is useful

The common case is being stuck on a paper puzzle with nowhere else to turn. It is also a good way to practise a specific position, to find out where you went wrong in a half-finished grid, or to see which techniques a puzzle from another source really needs.

A paper sudoku next to the app on a phone
From paper to the app. Click to enlarge.

Step 2

Start entering

Open the gear menu and choose Enter custom puzzle. The board is cleared, the cursor starts in the top-left cell (R1C1), and a line above the grid reminds you that you are in manual entry mode.

Fill in the given numbers with the number pad, starting at R1C1. After each number the cursor moves on to the next cell by itself, so you can read the puzzle row by row.

Gear menu with Enter custom puzzle ringed
Enter custom puzzle, in the gear menu.
The grid in manual entry mode with its banner
The banner reminds you that you are in manual entry mode.

Step 3

Skip the empty cells

Where the puzzle has an empty cell, press Skip to move on without entering anything. Skip and Done entering take the place of the Fill auto and Hint buttons while you are entering, since candidates and hints mean nothing until the puzzle is complete.

Close-up of the Skip and Done entering buttons
Skip and Done entering replace Fill auto and Hint while you enter.

Step 4 Premium

Done entering: the puzzle is checked

When all the givens are in, press Done entering. Before it lets you start, Grid9 checks two things:

  • No conflicts. If the same number appears twice in a row, column or box, the app lists the cells that clash and you stay in entry mode to fix them.
  • Exactly one solution. A proper sudoku has one and only one solution. If your grid has none, or more than one, the app says so and does not start.

The solution is needed so that hints, Check against solution and the mistake count all work. A typo is very often caught by one of these two checks. Not always, though: if a wrong digit happens to produce another valid puzzle, the app cannot know. So compare against the original once before you start.

Step 5 Premium

Solve it like any other puzzle

After the check the numbers you entered are the puzzle’s givens and the grid is a normal puzzle. Use your own notes or Fill auto, ask the hint panel what is available and climb the ladder as far as you like. See the Solving routine for the way I do it.

Mistakes are counted against the solution the app found, as in any other puzzle.

The step ladder on a puzzle
The same hint ladder, on your puzzle. Click to enlarge.

Note

Good to know

  • Entering a new puzzle replaces the one you are on.
  • Reset puzzle in the gear menu takes you back to the numbers you entered, so you can try a different route.

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Try it yourself

Entering your own puzzle is part of Grid9 Premium, with a free trial for new subscribers.

Coming soon to the App Store