Two more from the US Sudoku Qualifying Test in May — both geometric departures from regular sudoku.

As I consider the 2012 Irregular on the USSQT one of my best puzzles from that year, it was obviously going to be a challenge to do as well this time around. I felt the puzzle below was an adequate follow-up but certainly not as good as last year’s. The solve is meant to take advantage of the slightly irregular spacing of 1-6 in the patterned middle with the extra 7’s and 8’s giving a single solution. Note there are no 9s anywhere in the grid. Some Law of Leftovers steps will likely be encountered before the finish.

For the isodoku, just before the US Qualifier test, one of our readers here suggested I make a tutorial on some of the forced rules that come with these 3d shapes (this was after an isometric TomTom that strongly required solvers to know only 2 of each digit could appear on each face). I obviously couldn’t post such a tutorial just before the USSQT, but the properties of the 3D shapes was strongly in mind here. Often — like in the standard 2×4 rectangle form of an isodoku, or the 2012 USSQT Isodoku — there is a strong 2×2 square requirement that can split the digits into two distinct sets throughout the puzzle (see this colored solution of the 2012 for example). This year I wanted to choose a geometry that almost seems like it needs that 2×2 requirement in places, but here only three digits are highly constrained and the attempt to split the shape into patterns falls apart. Can you spot the three constrained digits and sort out where they must always go in this kind of geometry? Six particular cells are key.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Pattern in regions and digits

Rules: Standard Sudoku rules. The regions are not 3×3 boxes but are instead irregular shapes indicated by the bold lines.

Answer String: For the USSQT, the answer strings were a set of rows/columns encountered late in the puzzle. For this week, you can just hit the solved button on an honor system if you think you’ve solved it.

Solution: PDF

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Stacked boxes

Rules: Standard Isodoku rules, using numbers 1-8.

Answer String: For the USSQT, the answer strings were a set of rows/columns encountered late in the puzzle. For this week, you can just hit the solved button on an honor system if you think you’ve solved it.

Solution: PDF

I had not intended to have a repeat author for a Sunday Surprise so soon, but Craig Kasper sent along a really nice surprise sudoku to mark the US National Championship we’ve been focusing our attention on all weekend. See if you can find your way through to the very end.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: That US national championship happening this weekend; speaking of which, congratulations to the top finishers at the US Puzzle Championship, whomever you turn out to be.

Rules: Standard Sudoku rules. Also, the regions are irregularly shaped; instead of numbers, use the letters in “I’D GOLF, MAN” once in each row, column, and region.

Answer String: Enter the letters in the third column, from top to bottom, followed by the letters in the seventh column, from top to bottom. USE CAPITAL LETTERS.

Solution: PDF

PDF

or solve online (using our beta test of Penpa-Edit tools)

This is a “Twisted Tuesday” puzzle variation.

Theme: Big City

Rules: Standard Sudoku rules. Also, standard Skyscrapers rules.

Answer String: Enter the 8th column from top to bottom, followed by a comma, followed by the 9th column from top to bottom.

Time Standards (highlight to view): Grandmaster = 4:00, Master = 6:30, Expert = 13:00

Solution: PDF

This past week, another doctor made the mistake of appearing here. It seems trouble follows him everywhere, as puzzle creator Craig Kasper reveals here.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Dalek Invasion

Rules: Standard Sudoku rules except that instead of the numbers 1-9 this puzzle uses the letters in “END MATRIX”. Also, clues in the grid represent typical “Seek and Spell/Kanaore” clues; specifically, it must be possible to read each of the words/phrases listed below the grid by starting at the indicated number, moving one cell in the direction indicated by the arrow, and then continuing to move one cell at a time up, down, left, or right to complete the word/phrase. No cell may be used more than once in a single path, but the same cell can appear in the paths of different words/phrases.

Answer String: Enter the 2nd row from left to right, followed by a comma, followed by the 6th row from left to right. Use all capital letters.

Solution: PDF

PDF

or solve online (using our beta test of Penpa-Edit tools)

This is a “Twisted Tuesday” puzzle variation.

Theme: Doctor Sudo-Who?

Rules: Standard Sudoku rules except that instead of the numbers 1-9 this puzzle uses the letters in “WORD BATCH”. Also, clues in the grid represent typical “Seek and Spell/Kanaore” clues; specifically, it must be possible to read each of the words/phrases listed below the grid by starting at the indicated number, moving one cell in the direction indicated by the arrow, and then continuing to move one cell at a time up, down, left, or right to complete the word/phrase. No cell may be used more than once in a single path, but the same cell can appear in the paths of different words/phrases.

Answer String: Enter the 1st column from top to bottom, followed by a comma, followed by the 5th column from top to bottom. Use all capital letters.

Time Standards (highlight to view): Grandmaster = 5:00, Master = 7:00, Expert = 14:00

Solution: PDF

A few weeks ago Giovanni P. asked what our visitors might think about “other puzzles.” His question was specific to word puzzles, but this week I put the question to the test when I posted our first “Puzzle Hunt” puzzle. The Monday puzzle was not announced as such. Instead it was meant to just look like an April Fools joke. But it already has the most FAVEs of any puzzle on the site. So what are “Puzzle Hunt” puzzles and what was really going on with that word search?

(more…)

PDF

or solve online (using our beta test of Penpa-Edit tools)

This is a “Franken-Friday” puzzle variation.

Theme: Mostly Themeless! – Besides elements of symmetry and some patterning in the numbers, the design is focused on the logical solution path.

Rules: Standard Sudoku rules. Clues in the grid represent typical “Seek and Spell/Kanaore” clues; specifically, it must be possible to read each of the numbers listed below the grid by starting at the indicated letter, moving one cell in the direction indicated by the arrow, and then continuing to move one cell at a time up, down, left, or right to complete the number. No cell may be used more than once in a single number’s path, but the same cell can appear in the paths of different numbers.

Answer String: Enter the 3rd column from top to bottom, followed by a comma, followed by the 9th column from top to bottom.

Time Standards (highlight to view): Grandmaster = 7:00, Master = 12:30, Expert = 25:00

Solution: PDF

PDF

or solve online (using our beta test of Penpa-Edit tools)

Welcome to the new puzzle blog from Thomas Snyder, aka “Dr. Sudoku”, 3-time world sudoku champion and author of many books of puzzles including “The Art of Sudoku”. Here you will find a range of logic puzzles including number placement puzzles (such as Sudoku and TomTom), object placement (such as Battleships and Star Battle), region division (such as Fillomino and Cave), shading (such as Nurikabe and Tapa), path/loop (such as Slitherlink and Masyu) and many more.

Puzzles will get progressively harder throughout the week, so there will be easy puzzles for beginners on Monday and Tuesday to start the week and much harder puzzles by Friday and Saturday. Eventually there will be a random mix of many puzzle types every week, but as I start I will focus on two types each week, with Sudoku and TomTom leading the way. Puzzles will typically post at 9:00 AM Pacific Time.

This puzzle blog will have a few unique features. First, I want to actively track (and reward) the puzzle solvers. At the bottom of each post is a “solved” button. If you enter the correct answer string, your solution will be logged in. Eventually there will be leaderboards, contests, and prizes for people solving the puzzles. So if you solve the puzzles, log your success here. Mark your favorite puzzles too. So if a lot of solvers for example like TomTom over other styles, then you’ll see more of them here — and more TomTom books published.

Each puzzle has a “difficulty” posted too. This is just a recommendation from the expert/World Puzzle Championship level solvers who have helped test all the puzzles. The time has three values: the “Master” time, and then an “Expert” time (3x) and a “Novice” time (10x). Whatever level solver you are, these ratings should give you a sense of how hard a puzzle might be, and also give you a real sense of how well you are solving if you want to time yourself. But don’t start the stopwatch if you are just here for fun!

For any puzzle you really like, click on the tags to the left for more examples. Besides the posted puzzles, I will be releasing books with all of these puzzle styles. For Sudoku and Sudoku Variations and TomTom I already have books available for purchase. For the other styles, new titles like “The Art of Puzzles” will be coming soon.

This will be an exciting project, and I hope to see you visiting here a lot in the future. And if you have any recommendations for new puzzle styles, or want to make your own puzzle contributions here, just email me to start a dialogue.

Rules: The puzzle in this post is in the GMPuzzles logo. This is a Wordoku with a repeated letter so follow standard sudoku rules with a slight twist.

Time Standard: Sudoku Master = 2:30, Expert = 7:30, Novice = 25:00

Answer Check: USING CAPITAL LETTERS, enter the 8th row from left to right, followed by a comma, and then the 5th column from top to bottom (e.g. “GMPUZZLES,GMPUZZLES”)

Solution: PDF