61
This puzzle was set in celebration of Missing's 61st birthday.
Estimated difficulty: 2.5/5
Rules
Standard sudoku constraints: each row, column, and box must contain a complete set of the digits 1-9.
Standard killer cages: Digits in a cage indicated by a dashed line cannot repeat and must sum to the total shown in the upper left corner of the cage.
Standard whispers lines: Digits along green lines must differ by at least 5 and can repeat if allowed by other rules.
Standard renban lines: Digits along purple lines form a non-repeating set of consecutive digits that can appear in any order along the line.
Standard Kropki dots: Digits separated by a white dot differ by the amount shown in the dot. If no value is given in the dot, the digits differ by 1 (are consecutive). No negative constraint applies.
Cake
This puzzle is one of the few solo sets in our collection. FullDeck set it as a birthday gift to Missing a Few Cards.
Estimated difficulty: 2/5
Rules
Standard sudoku constraints: each row, column, and box must contain a complete set of the digits 1-9.
Standard killer cages: Digits in a cage indicated by a dashed line cannot repeat and must sum to the total shown in the upper left corner of the cage.
Standard whispers lines: Digits along green lines must differ by at least 5 and can repeat if allowed by other rules.
Standard renban lines: Digits along purple lines form a non-repeating set of consecutive digits that can appear in any order along the line.
Standard Kropki dots: Digits separated by a white dot differ by the amount shown in the dot. If no value is given in the dot, the digits differ by 1 (are consecutive). No negative constraint applies.
Solve in the CTC app (with decorative elements)
Solve in the CTC app (no decorative elements)
Modular Lines 2
This puzzle uses the modular entropic lines constraint introduced in Modular Lines 1 but is a bit harder.
Estimated difficulty: 3/5
Rules
Standard sudoku constraints: each row, column, and box must contain a complete set of the digits 1-9.
Standard killer cages: Digits in a cage indicated by a dashed line cannot repeat and must sum to the total shown in the upper left corner of the cage.
Modular Entropic Lines: Every set of three sequential digits along a line must contain a complete set of residues modulo 3, i.e. one digit from {1,4,7}, one from {2,5,8}, and one from {3,6,9}. Digits on two-cell lines cannot be from the same residue set. Digits may repeat on a line if allowed by other rules.
Modular Lines 1
This puzzle introduces a new constraint inspired by the entropic lines constraint created by Riffclown, JC Godart, Raumplaner, JeremyDover, and other setters in the Skunkworks Collective. Since it introduces a new constraint, this puzzle is intended to be fairly straightforward.
Estimated difficulty: 3/5
Rules
Standard sudoku constraints: each row, column, and box must contain a complete set of the digits 1-9.
Standard killer cages: Digits in a cage indicated by a dashed line cannot repeat and must sum to the total shown in the upper left corner of the cage.
Modular Lines: Every set of three adjacent digits on a line must contain a complete set of residues modulo 3. That is, for any set of three adjacent digits on the line, if you divide each by 3, one will have a remainder of 0, one will have a remainder of 1, and one will have a remainder of 2. Digits may repeat along the line if allowed by other rules.
Example: 579219 would be a legal sequence of digits along the line provided the 9's don't see each other in the row, column, or box. This is legal since the remainders form the sequence 210210 and any string of 3 digits in the remainder contains all three possible values.
Another way of thinking of this is that digits along the line are grouped into three sets: {147}, {258}, {369}. .
Jacks
This puzzle was inspired by the children's game of pick-up jacks. If you're too young to remember the exquisite pain of jacks left scattered on the floor, google it. Or just imagine Legos made of metal that always fall with a spike pointing up. Fun times!
Estimated difficulty: 2.5/5
Rules
Standard sudoku constraints: each row, column, and box must contain a complete set of the digits 1-9.
Thermos: Digits on thermometers must increase from bulb to tip but do not have to be consecutive.
Killer cages: Digits in cages indicated by dashed lines cannot repeat and must sum to the number shown in the upper left corner of the cage.
Lockout Labyrinth
Spring Break hit and our solving juices got flowing! Lockout Lines was set in an attempt to better understand this constraint and it turned into a lovely little puzzle. It also appears in the Indigestion Collection.
Estimated difficulty: 3/5
Rules
Standard sudoku constraints: each row, column, and box must contain a complete set of the digits 1-9.
Lockout lines: Digits in the diamonds at the ends of a lockout line must differ by at least 4. Digits on the line may repeat but cannot be equal to or between the digits in the diamonds.
Kropki dots: Digits on either side of a white dot are consecutive. Not all possible dots are shown.
DisArray
This puzzle came out of pondering how SET and disjoint groups might interact. Although it doesn't make use of SET, it's a fun puzzle. It has a unique solution without the kropki dots, but it's a painful slog with a lot of bifurcation to get there. The kropki dots make it a smooth solve and on the easier side, although definitely not a GAS puzzle.
Estimated difficulty: 2/5
Rules
Standard sudoku constraints: each row, column, and box must contain a complete set of the digits 1-9.
Standard arrow constraint: digits along an arrow must sum to the number shown in the attached circle and can repeat if allowed by other constraints.
Standard killer cage constraint: digits within a cage marked by a dashed border cannot repeat and must sum to the total shown in the upper left corner of the cage.
Standard kropki difference dot constraint: digits on either side of a white dot are consecutive. No negative constraint applies.
Standard disjoint groups constraint: Digits in the same relative position within boxes must be different.
All My Exes Lunch in Texas
All my exes live in Texas: as you can see, none of them are located outside the state! This puzzle was originally published as "All My Exes Lunch In Texas" as a nod to the use of sandwich sums for the CTC monthly puzzle prompt in January 2022: food and cuisine.
Estimated difficulty: 2.5/5
Rules
Normal sudoku rules apply. Digits along the Texas border (yellow line) alternate even/odd. Digits in cells separated by an X sum to 10. All possible Xs are shown. (Negative constraint applies). Digits along the purple (Renban) line are a set of consecutive digits, in any order. Number outside of the grid indicate the sum of the digits appearing between 1 and 9 in that column (sandwich sums).
Genetic Drift
This puzzle came out of playing with cloning roles and coloring strategies. A relatively straightforward puzzle, it has received several "great puzzle" and "beautiful theme" reactions in the CTC Discord channels.
Estimated difficulty: 2.5/5
Rules
Normal sudoku rules apply but cloning has gone horribly wrong. Four different gene cages (indicated by A, C, G, or T in the upper left corner) have replicated across the grid with mutations. Each copy of the original gene contains only digits from the original but order, orientation, and cage size may vary. Every copy of each gene (and its mutations) is indicated in the grid. For example, if gene A is 1-2, then every place that 1 is orthogonally adjacent to 2 in the grid will be marked with a gene cage labeled A. Bonds, indicated by white Kropki dots, have formed where two different genes have adjacent consecutive digits. All consecutive pair bonds between genes are indicated but there may be unmarked consecutive pairs within or outside gene cages.
Killing Me Primely
We set this puzzle because we just like prime numbers. It was the second puzzle we set together and at some point we will finish setting its partner, Killing Me Powerfully.
Estimated difficulty: 3/5
Rules
Normal sudoku rules apply. Digits in cages must sum to the number shown in the upper left corner of the cages (standard killer cage constraint). Numbers outside the grid indicate the sum of the digits along the diagonal shown (standard little killer constraint). Digits may repeat along little killer diagonals as long as they follow standard sudoku rules. NOTE: One of the little killer clues is there for aesthetic purposes; it's still true but not necessary!
Feast of the Seven Fishes
We have a tradition of eating Seven Fish Pie on Christmas Eve. That recipe (available here) was the inspiration for this puzzle, posted for the CTC monthly puzzle prompt in January 2022: food and cuisine..
Estimated difficulty: 2.5/5
Rules
Normal sudoku rules apply. The purple fish are Renbanfish, consisting of a set of consecutive digits in any order. The green fish are German Whisperfish and successive digits along the fish must differ by at least 5. The anglerfish at the bottom of the grid is a thermo and digits must strictly increase from bulb to tip. Bubbles in the water are kropki difference dots; digits on either side of the bubble form a consecutive pair. The black dots are kropki fish food; digits on either side are in a 1:2 ratio. Not all possible dots are given.
Snowdrops
Snowdrops was the first puzzle we set together. It was created in response to the CTC Discord monthly puzzle prompt for December 2021: ice and cold. We are inordinately pleased that our first puzzle together received "mind-blowing puzzle" and "beautiful theme" reactions. Snowdrops also appears in the Showcase Collection. It has two variants, shown below.
Estimated difficulty: 3.5/5
Rules
The sun is shining but a few flakes of snow are beginning to fall, represented in this puzzle by white circles. Is the temperature dropping?
Normal sudoku rules apply. Digits along an arrow must sum to the number indicated in the circle from which the arrow emerges (standard arrow constraint). Digits on thermometers strictly increase from bulb to tip but are not necessarily consecutive (standard thermo constraint). Cells separated by a white dot are consecutive (standard Kropki difference constraint). In addition, cells that are a chess king's move apart cannot contain the same digit (standard anti-king constraint).
Six Snowdrops
We set this puzzle as one of two variants to Snowdrops. The solve has the same initial path but different snowflakes lead to a different solution.
Estimated difficulty: 3.5/5
Rules
The sun is still shining but the snow is falling faster. The snowdrops are reaching for the sky.
Normal sudoku rules apply. Digits along an arrow must sum to the number indicated in the circle from which the arrow emerges (standard arrow constraint). Digits on thermometers strictly increase from bulb to tip but are not necessarily consecutive (standard thermo constraint). Cells separated by a white dot are consecutive (standard Kropki difference constraint). In addition, cells that are a chess king's move apart cannot contain the same digit (standard anti-king constraint).
Raindrops and Snowdrops
This is the second variant to Snowdrops. Again, a similar entry to the puzzle but a different constraint changes up the logic and solution a bit. Estimated difficulty: 3.5/5
Rules
The sun is still shining but the rain is starting to fall. Will the rain make the snowdrops grow?
Normal sudoku rules apply. Digits along an arrow must sum to the number indicated in the circle from which the arrow emerges (standard arrow constraint). Digits on thermometers strictly increase from bulb to tip but are not necessarily consecutive (standard thermo constraint). Cells separated by a black dot are in a 2:1 ratio (standard Kropki ratio constraint). In addition, cells that are a chess king's move apart cannot contain the same digit (standard anti-king constraint).
Twelfth Knight
A much more challenging follow-up to Chivalry, Twelfth Knight requires heavy lifting from the anti-knight constraint to break into the cages. It is a challenging puzzle even for experienced solvers and has garnered consistent reactions of "exceptional puzzle" and "beautiful logic" from the CTC Discord community. Twelfth Knight also appears in the Showcase and was the first puzzle we posted to LogicMasters Deutschland.
Estimated difficulty: 3/5
Rules
Standard sudoku rules apply. Digits within a cage cannot repeat and must sum to the total shown in the upper left corner of the cage (standard killer cage constraint). The same digit cannot appear in cells a chess knight's move apart (standard anti-knight constraint).