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

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between Sudoku entry modes and a shading mode to mark off clues.)

Theme: Almost all in order – two double 1-9 digit pangrams and two single 1-9 digit pangrams are on the outside of this grid.

Rules: Standard Outside Sudoku rules.

Answer String: Enter the 5th column from top to bottom, followed by a comma, followed by the 9th column from top to bottom.

Time Standard: Outside Sudoku Grandmaster = 6:15, Master = 10:15, Expert = 20:30

Solution: PDF

PDF

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

Theme: Countdown!

Rules: Standard Skyscrapers rules.

Answer String: Enter the 8th row from left to right, followed by a comma, followed by the 1st column from top to bottom.

Time Standard: Skyscrapers Grandmaster = 5:15, Master = 8:00, Expert = 16:00

Solution: PDF

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between Sudoku entry modes and a shading mode to mark off clues.)

Theme: A series of series (and a constant and a square) — The seemingly random numbers outside the grid actually have some rhyme and reason.

Rules: Standard Outside Sudoku rules.

Answer String: Enter the 7th row from left to right, followed by a comma, followed by the 4th column from top to bottom.

Time Standard: Outside Sudoku Grandmaster = 5:00, Master = 7:00, Expert = 14:00

Solution: PDF

PDF

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

Theme: Either/or — a hard solving theme despite so many clues.

Rules: Standard Skyscrapers rules.

Answer String: Enter the 3rd row from left to right, followed by a comma, followed by the 4th column from top to bottom.

Time Standard: Skyscrapers Grandmaster = 3:00, Master = 5:30, Expert = 11:00

Solution: PDF

Note: Advice on solving this puzzle, and also constructing Skyscraper puzzles, has now been posted in “Ask Dr. Sudoku #6”

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between Sudoku entry modes and a shading mode to mark off clues.)

Theme: Four Nonets

Rules: Standard Outside Sudoku rules.

Answer String: Enter the 5th row from left to right, followed by a comma, followed by the 5th column from top to bottom.

Time Standard: Outside Sudoku Grandmaster = 2:15, Master = 3:00, Expert = 6:00

Solution: PDF

PDF

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

Theme: A little of everything — the rows have clues from 1 to 6.

Rules: Standard Skyscrapers rules.

Answer String: Enter the 4th row from left to right, followed by a comma, followed by the 5th column from top to bottom.

Time Standard: Skyscrapers Grandmaster = 1:00, Master = 1:45, Expert = 3:30

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.

(more…)

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.

PDF

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

Theme: Jekyll and Hyde – digits but no bars up top, bars but no digits down below. Master both sides to solve this puzzle.

Rules: Standard Consecutive Sudoku rules.

Answer String: Enter the 1st column from top to bottom, followed by a comma, followed by the 9th column from top to bottom.

Time Standard: Consecutive Sudoku Master = 4:30, Expert = 13:30, Novice = 45:00

Solution: PDF and solving video.