Guidance for Puzzle Submissions

If you create a puzzle/sudoku that you'd like to see us solve on Cracking The Cryptic then a) FANTASTIC! And b) Please, when sending your submission to us, do make sure you adhere to the following requirements. These help our testers to get through the sheer volume of requests we receive. Thank you.

  1. Make sure your puzzle has been test-solved and contains no errors.

  2. Please indicate in the covering email your preferences as regards your puzzle - i.e. are you only looking for it to appear in a video on the channel; or, if we decide not to video it but like the puzzle, are you happy for us to release it as a community post or on patreon (free or behind the paywall)? “Use it how you choose” covers everything!

  3. Your puzzle email should include:
    1. the puzzle presented exactly as you'd like our testers to see it;
    2. on a separate page, the solution. The solution should include a description of any difficult/interesting steps in the logical path. This is not for Simon & Mark but is to aid the testers. We endeavour not to publish puzzles that require bifurcation/guesswork so, if a tester feels their only chance to crack a difficult puzzle is using such techniques then it is very likely the puzzle will be rejected. By including the logic path, the tester may appreciate that some logical step WAS reasonable and so still pass the puzzle on to Simon & Mark.

  4. Send the above to: crackingthecryptic@gmail.com Please be aware that we do not have time to reply to submissions. You should assume that, if you hear nothing and the puzzle has not appeared in a video/community post/patreon post within a month then, unfortunately, we have not decided to use the puzzle. At this point, by all means do submit another puzzle (but please do wait this one month period before doing so).

CTC Sudoku Style Guide

This guide is designed to give you the best chance of your puzzle being featured. Great puzzles will be featured even if they don’t conform – but the chances for any puzzle will increase if the guidelines are followed!

Please try and use the following wordings for rules, colours for lines, and other details below when submitting puzzles for consideration by CTC for feature on the channel. Given the volume of puzzles that Simon and Mark receive as recommendations or requests, the less work they have to do to understand or adjust what you send, the more likely your puzzle is to be tested and perhaps featured.

If there is something special about your puzzle that its appearance creates or enhances, and therefore you would like to deviate from the following (especially using coloured cells or lines in your puzzle), please provide a brief explanation of why – don’t expect the testers or Simon or Mark to recognise your intention. (For example, using yellow, black, and red lines for a German Whispers puzzle, reflecting the colours of the German flag, in honour of the celebration of the reunification of Germany – spell it out, don’t assume that they will get it.)

The wordings of the rules that follow are designed to be succinct and clear. If your puzzle has a ruleset that is different from what is here, please use the principles that you find here as guides to how to word your rules. CTC may change the wording of rules that you provide if they feel that clarity or brevity would be enhanced. In particular, the description box contents of YouTube videos are somewhat constrained, so rules must frequently be pared down to their essentials (without sacrificing clarity, we hope).

The following rules/guidelines are grouped according to the type of marking or constraint they are: general guidelines, markings in the grid, lines, markings outside the grid, and constraints that are unmarked but apply generally to a puzzle.

General guidelines:

Please use standard English capitalisation conventions. This usually means that only the first word in a sentence is capitalised (e.g., “Normal sudoku rules apply.”); the names of countries or languages are capitalised (German, Dutch); the symbol X or V for a puzzle that uses those markings should be capitalised; for the most part other words should not be capitalised.

In the grid, please do not use coloured cells unless it is essential to the structure and functionality of your puzzle. (If you want to use coloured cells to create an image or represent a thematic element of your puzzle, please explain what you are trying to achieve.)

Please specify whether there are any negative constraints. (“Not all dots are given”; “All Xs and Vs are given”).

In a sudoku/puzzle hunt or multi-page document, please use consistent markings and wordings for rules throughout. In addition, please number the pages or number the puzzles (or both) unless there is a reason not to do so that is integral to the solution or experience (and please provide an explanation as to why you do not wish to do so).

Markings in the grid:

Kropki dots: Digits in cells joined by a white dot are consecutive. Digits in cells joined by a black dot are in a 1:2 ratio. (i.e., one digit will be double the other).

X/V: Digits in cells joined by an X sum to 10. Digits in cells joined by a V sum to 5.

Odd/Even: A digit in a grey square is even. A digit in a grey circle is odd.

Extra regions: Place 1-9 in each row, column, box, and shaded region (instead of ‘Normal sudoku rules apply’).

Clones: Shaded regions are clones of one another; digits appear in exactly the same positions in each shaded region.

Killer: Digits in a cage may not repeat and sum to the total given.

Fortress: A digit in a shaded cell must be higher than a digit in an orthogonally adjacent unshaded cell.

Quadruples: Digits in a circle must appear within the four surrounding cells.

Lines:

Please use the colours indicated for the following lines. If a particular image or picture is being made, you can deviate from the line colours given, but please provide an explanation of why you desire to do this. Do not use opposite colours in the same puzzle (for example, in the same grid do not use green for Renban lines and purple for German whispers lines). There are quite a number of programs now for creating sudoku grids. If you use one of those, don’t worry too much about specified thicknesses and diameters below, but we would certainly prefer to receive the puzzle playable in CTC software/sudokupad.

Arrow: (thinner grey line, attached hollow circles at .85 cells in diameter) Digits along an arrow sum to the number in the attached circle.

Thermometer: (thicker grey line, bulb as attached grey disks at .75 cells in diameter) Digits along a thermometer increase from bulb to tip.

Renban (purple line): Digits along a purple line form a set of consecutive digits in any order.

German whisper (green line): Neighbouring/adjacent digits along a green line have a difference of at least 5.

Dutch whisper (orange line) Neighbouring/adjacent digits along an orange line must have a difference of at least 4.

Palindrome: (grey line if possible, preferably orange if not) Digits along a palindrome read the same in both directions.

Diagonal: (blue diagonal) digits along the marked diagonal(s) must not repeat.

Between-line: (black line, hollow black diamond/square at .85 cells diameter) Digits along a line are strictly between the digits in the circles on the ends of the line.

Equal-sum line: (blue lines) Box/region borders divide a blue line into segments which have the same sum. Different lines may have different sums.

Markings outside the grid:

Sandwich: A clue outside the grid gives the sum of the digits appearing between the 1 and the 9 in that row/column.

X-Sums: A clue outside the grid gives the sum of the first X digits of that row or column from the direction of the clue, where X is the digit placed in the cell next to the clue.

Little killer: A clue outside the grid gives the sum of the digits along the indicated diagonal.

Skyscraper: A clue outside the grid gives the number of skyscrapers visible from that position looking along the row or column, where each digit’s value indicates the height of the skyscraper.

Unmarked/other constraints:

Non-consecutive: Digits in orthogonally adjacent cells must not be consecutive.

King’s/Knight’s move (or antiking/antiknight): Identical digits cannot appear in cells a chess knight’s/king’s move apart.

Entropic: Any sequence of 3 digits [along a line] must have a low digit (123), a medium digit (456) and a high digit (789).