Absolute GAS
The solve path for this is all naked singles, meaning that at every step there is at least one digit that can be placed immediately. This puzzle is so pretty that we didn’t feel we created it but rather discovered it, and that it should be shared. The community seems to agree, having awarded it several "mind-blowing puzzle" and "beautiful logic" reactions. It is currently in the top 20 most solved puzzles of all time on LogicMasters Deutschland.
We are particularly delighted that this puzzle helped inspire the brilliant setter Philip Newman to find new "smallest known givens" for thermo constraint puzzles. (You'll have to join the Discord server to see his post and lovely puzzle.)
Estimated difficulty: 1/5
Rules
Standard sudoku rules apply. Digits on thermometers increase from bulb to tip.
Turbulence
The product of sleepless night, this puzzle also appears in the Heartburn Collection.
Estimated difficulty: 3.5/5
Rules
Standard sudoku rules apply. Digits along an arrow sum to the number in the attached circle and may repeat if permitted by standard sudoku constraints (standard arrow constraint). Digits separated by a white dot form a consecutive pair. Digits separated by a black dot are in a 1:2 ratio (standard kropki dot constraints).
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. It also appears in Indigestion Collection 1.
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.
All My Exes Live 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. It also appears in Indigestion Collection 1.
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).
Nice Hot Cuppa
With snow in the forecast, let's settle in with a nice hot cuppa! This was our second puzzle posted for the CTC monthly puzzle prompt in January 2022: food and cuisine. It also appears in the GAS Collection.
Estimated difficulty: 2/5
Rules
Standard sudoku rules apply. Digits along each gray line read the same forwards as backwards along the line. Digits can repeat along palindromes provided they follow normal sudoku constraints (standard palindrome rules). Digits shown within a circle must appear in one of the four cells adjacent to the circle (standard quadruple rules).
Maelstrom
Find your way carefully into the swirling wind of constraints on this puzzle, which also appears in the Heartburn Collection.
Estimated difficulty: 3.5/5
Rules
Standard sudoku rules apply. Digits along an arrow must sum to the number in the connected circle and may repeat if permitted by normal sudoku rules (standard arrow rules). Numbers outside the grid indicate the sum of all the digits along the diagonal indicated by the arrow (standard little killer rules). Digits can repeat along the diagonal if permitted by normal sudoku rules.
Do You Want to Know a Secret?
Simon Anthony has a secret, a secret that he only tells his closest friends. (As of this writing, there are only 435,000 of them.) This puzzle will help you practice using this secret! An introduction to killer cage and locked sets logic, this puzzle also appears in the Brassica Collection.
Estimated difficulty: 1/5
Rules
Normal sudoku rules apply. Digits inside the cages marked by dashed lines add up to the small number in the corner of the cage.
Something to think about: What are the digits in every row, column, and box? What do they add up to?
Exes and Dots and Vees, Oh My!
This puzzle introduces new constraints to go along with kropki dots for someone new to variant constraint logic. It also appears in the Brassica Collection.
Estimated difficulty: 1/5
Rules
Roman Numerals and New Ratios
Black dots with "3" in the center indicate that one of the cells they join is 3 times the other. For example, 6 and 2 could be on either side of a black dot in this puzzle.
Cells joined by a "V" must add to 5. For example, if a 2 is on one side of a V, the digit on the other side must be a 3.
Cells joined by an "X" must add to 10. For example, if a 2 is on one side of a X, the digit on the other side must be an 8.
Melting Gummy Worms
This puzzle focuses on thermo logic and elimination of possibilities using locked sets for someone who has started to become comfortable with kropki dot logic. It also appears in the GAS Collection.
Estimated difficulty: 1/5
Rules
Normal sudoku rules apply. White dots mark pairs of consecutive digits. Not every pair of consecutive digits is marked with a white dot.
Now, what about those gummy worms? Those are actually thermometers, and as with any thermometer, the further you go from bulb to tip the higher the digit. Digits on thermometers do not have to be consecutive but could be.
Brassica Dots and a Thermo
This puzzle is intended as a first introduction to thermos for someone who has started to become comfortable with kropki dot logic. This puzzle also appears in the Brassica Collection.
Estimated difficulty: 1/5
Rules
Normal sudoku rules apply. Cells separated by a white dot contain consecutive digits. If two cells are separated by a black dot, one is double the other. Some possible dots may not be shown. Digits on the thermometer increase from the bulb to the tip but do not have to be consecutive.
Driving Me Dotty
This puzzle is part of our Brassica-to-Gas series. Puzzles in this series have a Brassica version as well as a GAS version. This version, at the GAS level, has earned many reactions of "great puzzle" from the CTC Discord community and also appears in the GAS Collection. An easier version appears in the Brassica Collection.
Estimated difficulty: 2/5
Rules
Normal sudoku rules and standard Kropki dots apply. (Digits separated by a white dot differ by 1. If two digits are separated by a black dot, then one is twice the other.) Not all possible dots are shown.
Category 6: Eye of the Storm
This puzzle has some nice early logic to resolve the long dot chains. It has earned many reactions of "great puzzle" from the CTC Discord community and also appears in the GAS Collection. An easier version is posted in the Brassica Collection.
Estimated difficulty: 2.5/5
Rules
Normal sudoku rules and standard Kropki dots apply. (Digits separated by a white dot differ by 1. If two digits are separated by a black dot, then one is twice the other.) Not all possible dots are shown.
Salt and Pepper
We set this puzzle as our first response to the CTC Discord monthly puzzle prompt for January 2022: puzzles related to food and cuisine. It has earned many reactions of "great puzzle" and "beautiful theme" from the CTC Discord community. Salt and Pepper also appears in the GAS Collection. It has enough solves (>150) and a sufficiently high beauty rating on LMD to have been placed in the LMD "often solved and nice" list, gaining it a place in our showcase.
Estimated difficulty: 2/5
Rules
The salt shaker on the upper left is a Renban line consisting of a set of consecutive digits in any order. The pepper shaker on the upper right is a German whispers line with each cell differing by at least five from neighboring cells along the line. Digits cannot repeat along the salt shaker or along the pepper shaker. The digits in the large circles at the tips of the shakers must appear in the four surrounding cells.
The numbers in the salt grains (white Kropki dots) tell the difference between the cells they join. The numbers in the pepper flakes (black Kropki dots) tell the ratio between the two cells they join.
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 Indigestion Collection 1. It was the first puzzle we posted to LogicMasters Deutschland.
Estimated difficulty: 3.5/5
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).