There is no Doctor’s Note this week.

Seventh in a series with puzzle solving tips. This time with advice on exploring unusual puzzle geometries such as the Saturday Sudo-Kurve.

When you’ve solved enough 3d Sudoku or Sudo-Kurve puzzles or other unique geometries (as in Sudoku Masterpieces), you’ve probably recognized there are sometimes cells or sets of cells that are much more constrained than others in the construction. This Sudo-Kurve grid, which I used in Sudoku Cup 3 and only one other time since, has some secrets to observe before getting too deep into any puzzle.

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Sixth in a series with puzzle solving tips. This time with advice on both solving and constructing skyscrapers puzzles.

I’ve gotten a lot of requests for tips on how to construct puzzles. I don’t offer many online as I have a monthly column in GAMES magazine that covers this and I don’t like competing with myself for less money. But Mike Selinker and I have improved on that content recently in turning our columns into a book, Puzzlecraft: The Ultimate Guide on How to Construct Every Kind of Puzzle. Please check it out.

This week, I thought I would give some insights into how I made this puzzle. Since I often construct a puzzle by thinking in the same way that I would solve the puzzle, the images below will show you both how I made the grid (and when I needed to use certain clues) and also how solvers likely completed the grid (and when they needed to use certain clues).

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No real news this week. I’m moving away from San Francisco, so this week and next will be pretty brief Doctor’s Note-wise.

This coming week contains Tapa and Sudo-Kurve puzzles. As I’ve never posted a *classic* Tapa puzzle despite writing several, I needed to make a new example worthy for posting tomorrow on the Rules page. This example (about Wednesday difficulty) is a bonus puzzle for today, and there will be three more Tapa puzzles throughout the week.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the composite Yajilin mode where left click marks cells, right click marks dots in cells or X’s on edges, left click+drag draws lines.)

Theme: Quadrants

Rules: Shade some squares black to create a single connected wall. Numbers in a cell indicate the length of consecutive shaded blocks in the neighboring cells. If there is more than one number in a cell, then there must be at least one white (unshaded) cell between the black cell groups. Cells with numbers cannot be shaded, and the shaded cells cannot form a 2×2 square anywhere in the grid.

Answer String: Enter the length of shaded segments, from left to right, in each of the indicated rows. Separate each row’s entry from the next with a comma.

Time Standard: Tapa Grandmaster = 1:00, Master = 2:00, Expert = 4:00

Solution: PDF

Fifth in a series with puzzle solving tips. This time, with some advice on global constraints that arise in loop puzzles.

Some of you have asked why I don’t put “general tips” up before I post any puzzles. I find that learning how to solve puzzles is more interesting than reading how to do every single step. I won’t post a list of the top 20 Slitherlink patterns you should memorize, for example, on the rules and info page. Most of you would probably get more enjoyment figuring those out for yourself. But, after you’ve solved a challenge, I do like highlighting some of the things as constructor I tried to include, perhaps as a lesson for the future. This is what I will do this week with parity constraints for the Friday Masyu.

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We’re now halfway through what I’ve been calling the “introduction” phase of Grandmaster Puzzles, in which I introduce the majority of the genres I’ll be including in my next few books, both as author and as editor. After the “introduction” phase, there will be puzzles by some other talented puzzle constructors here. And I hope to have over half of the puzzles in The Art of Puzzles written by others, maybe even you. I’ll be sending a detailed contributor email out by the end of the week so if you haven’t contacted me yet with interest in writing puzzles for these projects, now is the time to do so.

After the discussion last week, I’ve decided to change my reported time standards a bit. First, “Grandmaster” will be introduced and will be equivalent to about where Master was set before, timed close to my best test-solver and equivalent to where I expect someone in the top 10 in the world to be. Master will now be set around the median of my group of solvers, which will be about where a 10th place USPC finisher will be or about top 100 in the world. In some sense these two times will inform on the mean and s.d. of the puzzle, and can highlight the Aha nature versus speed nature of particular solves as I have a few where one solver blazes through but the average solve takes much longer. Expert will be set at 2x the new Master time, which will often be close to the old 3x of GM but is hopefully more stable as it is using many more solvers’ data. There will no longer be a Novice time. It has not been a very useful measure at all, and I think has encouraged more disappointment than cheer from people trying to target it.

Next week will be “Think Outside the Box” week, with two puzzle styles where the clues are outside the grid. That should be a pretty easy Puzzle and Sudoku pair to identify, and I hope you enjoy the set of challenges I’ve lined up.

Best,
Dr. S.

Fourth in a series with puzzle solving tips. This time, basic steps to get through Cave puzzles.

While I’ve already written a good description of solving Cave (Corral) puzzles for the USPC, I’ve never drawn up some of the steps for more visual solvers. This week I hope to fix that by highlighting one of the more fundamental logic steps behind these puzzles.

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Still recovering from my trip to Boston so this week’s note will be brief. I hope you enjoyed the Arrow Sudoku and Cave Puzzles. This coming week will bring the first of the loop puzzle genres, Masyu, and Consecutive Sudoku, another of my favorite sudoku variants from the past, in this case from explorations in Mutant Sudoku.

As the topic for this week, I want to know what you think of the times given with the puzzle each day. For the competitive puzzlers, do you like seeing these times? Is the master time a bit too hard to reach? Would a slightly easier standard give a better target? For the recreational puzzlers, does seeing a time change how you approach the puzzle to care more about the clock than otherwise? Would you like an option to keep them hidden instead?

I am considering adding a self-reporting of times to the solve box once there is a finishers page for each puzzle. It is not a high priority at the moment as I view the times as a guideline to set an expectation for the puzzle, and not yet that my site is a “competitive puzzle site” like some others that record solving histories and such. But I welcome your input on any changes you might like me to think about going forward since I do have several excellent testers that have been giving me good data every day.

Cheers,
Dr. S

Third in a series with puzzle solving tips. This time, a dissection of Saturday’s Star Battle.

Jack Bross left an excellent set of starting tips for Star Battle in Dr. Sudoku Prescribes #14 so if you are struggling with these puzzles, start there. The hard Saturday puzzle required some unusual group recognition which I thought deserved to be highlighted.

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Today is probably the last day of the MIT Mystery Hunt and I’ll be puzzled out for the next few days, but I wanted to offer another Doctor’s Note on the state of Grandmaster Puzzles. After Jack Bross’s frightening guess of Thermo-Sudoku and Star Battle last week, I’m sure he can divine — when I say my favorite (non-Snyder) Sudoku variant, and my favorite “underrepresented” puzzle are coming this week — what you’ll see throughout the next six days.

After three weeks of puzzles, I wanted to hear your initial impressions on the puzzle difficulties here. Do you appreciate seeing a mix from “Monday” to the end of the week? Are some puzzles too trivial or too hard? Obviously some solvers will be in a very different part of their learning curves so I hardly expect to be able to satisfy everyone.

Finally, I wanted to thank Bram de Laat this week for helpful insight on the origins of Star Battle that have been added to that rules page. In addition to Bram, Wei-Hwa Huang and Nick Baxter have been particularly helpful in some of the research I’ve needed for puzzle origins and a thank you goes out to both of them as well.

— Dr. Sudoku

Second in a series with puzzle solving tips. This time, Nurikabe solving tips for last Friday’s puzzle.

A few simple Nurikabe rules will get you through most of the puzzles quite fast; but some of these rules are uncommon enough that you mainly learn them from solving rare puzzles like ours.

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