Dr. Sudoku Prescribes #63 – Skyscrapers

Skyscrapers by Thomas Snyder

PDF

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

Theme: On a scale of difficulty from one to five — this is “Mostly Five”

Rules: Standard Skyscrapers rules.

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

Time Standards (highlight to view): Grandmaster = 5:45, Master = 10:00, Expert = 20:00

Solution: PDF

Editorial Note: This should go without saying, but it is advised that you pursue logic as far as you can take it instead of guessing.

Dr. Sudoku Prescribes #62 – Sudoku (Seek and Spell)

Sudoku Variation by Thomas Snyder

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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

Dr. Sudoku Prescribes #61 – Nurikabe

Nurikabe by Thomas Snyder

PDF

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

Theme: Rubber Band – the set of middle clues will stretch your mind a bit.

Rules: Standard Nurikabe rules.

Answer String: Enter the length in cells of each of the black segments (the unnumbered, connected “ocean”) from left to right for the marked rows, starting at the top. Separate each row’s entry from the next with a comma.

Time Standards (highlight to view): Grandmaster = 2:15, Master = 3:00, Expert = 6:00

Solution: PDF

From the Foxger’s Den #8: Cave

Cave by Grant Fikes

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between shading mode and the linex mode where left click+drag draws lines and right click marks X’s)

Theme: Spelunking 101

Rules: Standard Cave rules.

Answer String: Enter the length in cells of each of the cave segments from left to right for the marked rows, starting at the top. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 1:45, Master = 3:00, Expert = 6:00

Solution: PDF

Note: Follow this link for other Cave variations and this link for other classic Caves. If you are new to this puzzle type, here are our easiest Cave Puzzles to get started on.

From the Foxger’s Den #7: Battleships (Yajilin)

Battleships (Yajilin) by Grant Fikes

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between Battleships placement and line drawing modes.)

This is a “Twisted Tuesday” puzzle variation.

Theme: A Fleet of Clues

Rules: Variation of Battleships rules. Place the fleet of ships in the grid so that no ships touch each other, even diagonally. The grid contains internal clues (a number and an arrow) that show how many ship segments are in the indicated direction. All remaining cells containing neither a ship nor a clue must be able to form a single loop, as in a Yajilin puzzle (see for example here but note the “black square rules” are replaced with battleships placement rules).

Answer String: For each row from top to bottom, enter the number of the first column from the left where a ship segment appears. If the row is empty, enter 0. Enter these numbers as a single string with no separators.

Time Standards (highlight to view): Grandmaster = 2:30, Master = 4:00, Expert = 8:00

Solution: PDF

From the Foxger’s Den #6: Masyu

Masyu by Grant Fikes

PDF

or solve online (using our beta test of Penpa-Edit tools in linex mode where left click+drag draws lines and right click marks X’s)

Theme: Mostly themeless? A mostly straight-forward puzzle to start the week.

Rules: Standard Masyu rules.

Answer String: Enter the length in cells of the horizontal loop segments from left to right in the marked rows, starting at the top. If the loop only has vertical segments in the marked row, enter 0. Separate each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 0:45, Master = 1:15, Expert = 2:30

Solution: PDF

Doctor’s Note #11 – And Then There Were Two…

I hope you enjoyed the first week with Grant Fikes contributing puzzles. Grant will be a regular author in the future, and has already sent in a lot of outstanding puzzles for The Art of Puzzles. While his best puzzles and his largest puzzles (sometimes one and the same) will be saved for that publication, a lot of fine leftovers will still end up here on a weekly basis. In other words, if you’ve enjoyed what you’ve seen here you’ll be amazed by what is in the book. Still, if you’d like to see some “Giants” from Grant, please check out the three he released last weekend 600 (LITS/”Tetra Firma”), 601 (Shakashaka/”Proof of Quilt”), and 602 (Norinori/”Dominnocuous”).

Who will our next Contributing Puzzlemaster be and when will his or her puzzles first appear? Only time will tell. For now I wanted to announce that the weekly release schedule will be going through a few changes. Since I have been publishing Sudoku and puzzles in five other genres (object placement, number placement, loops, shading, and region division), for most weeks going forward there will now be one puzzle in each of those six areas. Every other week will have a change in types (for example Masyu this week, Slitherlink the next) so there will be some balance in what gets posted. Over time, the genres will cycle through each day of the week so that easier and harder puzzles of all styles appear. That’s the basic plan, but there may be a few other surprises in store.

Finally, since a small number have been asking for more hints on the hidden contest (which remains undiscovered), and since I’ve not been responding privately for the sake of fairness, now seems a good time to narrow the hunt somewhat. While there have been a lot of posts here, from Doctor’s Notes to solving tutorials, this site is primarily about the puzzles. Somewhere in those 60 posts is what you need to find the “+1 puzzle” and possibly win a free book.

Regards, Dr. S.

PS: There will be no “Ask Dr. Sudoku” this week, but if you have any questions you would like answered in a future column, or past puzzles that have appeared here that were not covered that you would like some more insights on, this is the time to inquire. Going forward, I intend the “Asking” to be more active and cover just about anything (from puzzle that use baskets to NCAA tournament brackets). Solving/construction tutorials are interesting, but are not meant to be the only kind of topic.

From the Foxger’s Den #5: Cross the Streams

Cross The Streams by Grant Fikes

PDF

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

Theme: Two Hard!

Rules: Standard Cross the Streams rules.

Answer String: Enter the length in cells of each of the black segments from left to right for the marked rows, and from top to bottom for the marked columns, going in order from A to B to C to D and separating each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 5:45, Master = 11:15, Expert = 22:30

Solution: PDF

From the Foxger’s Den #4: Star Battle

Star Battle by Grant Fikes

PDF

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

Theme: Author’s monogram

Rules: Standard Star Battle rules. Two stars per row, column, and region.

Answer String: For each row from top to bottom, enter the number of the first column from the left where a star appears. Enter these numbers as a single string with no separators.

Time Standards (highlight to view): Grandmaster = 2:45, Master = 4:30, Expert = 9:00

Solution: PDF

Note: Follow this link for other classic Star Battles and this link for Star Battle variations. If you are new to this puzzle type, here are our easiest Star Battles to get started on. More Star Battle puzzles can be found in The Art of Puzzles, in the book Star Battle by JinHoo Ahn, and in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli.

From the Foxger’s Den #3: Cross the Streams

Cross The Streams by Grant Fikes

PDF

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

Theme: Happy Pi Day!

Rules: Standard Cross the Streams rules.

Answer String: Enter the length in cells of each of the black segments from left to right for the marked rows, and from top to bottom for the marked columns, going in order from A to B to C to D and separating each row’s entry with a comma.

Time Standards (highlight to view): Grandmaster = 3:14, Master = 5:30, Expert = 11:00

Solution: PDF

Editor’s Note: Or, for our less pi-ous solvers, Happy Tau/2 Day as well! We’re very open-minded here at GMPuzzles.