Editor’s Note: While our Sunday Surprises are meant to be unexpected, today’s surprise should be a double surprise for you. Besides the bonus puzzle, it is my great pleasure to announce that one of the world’s best puzzlemakers and the inventor of Tapa, Serkan Yürekli, is joining us as a regular contributor. (If you haven’t yet, you should check out his Tapa Variation Contests that are starting again this weekend and his Classic Tapa Contest that starts next week.)

I asked Serkan, for his debut week, to provide some of the puzzle styles I know him best for and I hope you will enjoy what is in store. Today brings a “The Persistence of Memory” puzzle that Serkan wrote with GMPuzzles in mind.

(View image directly for larger form.)

(PNG with extra lines for solvers who want to flood-fill the path)

or solve online (using our beta test of Penpa-Edit tools using a composite mode where left click inside cell shades square, left click + drag draws line segment, right click inside cell adds dot, and right click on cell edge adds an x.)

PDF

Theme: GMPuzzles

Rules: Find a path from one dot to the other by moving horizontally or vertically between adjacent squares. The path cannot touch itself, even diagonally. All highlighted regions must be used, and may be re-entered. If two or more highlighted regions have the same shape and orientation, then how the path passes through those shapes must be identical. Or see here.

Answer String: For each marked row, enter the size of each group of cells used by the path from left to right. Separate each row with a comma.

Time Standards (highlight to view): Grandmaster = 7:30, Master = 10:30, Expert = 21:00

Solution: PDF

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)

This is a “Twisted Tuesday” puzzle variation.

Theme: All Cells and All Antisymmetry!

Rules: Standard Masyu rules. Also, ALL CELLS must be visited by the loop.

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 = 1:45, Master = 2:30, Expert = 5:00

Solution: PDF

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: Almost Twisted Symmetry

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 = 1:00, Expert = 2:00

Solution: PDF

PDF

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

Theme: Clue symmetry and logic

Rules: Standard Yajilin 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 = 4:30, Master = 7:30, Expert = 15:00

Solution: PDF

(View image directly for larger form.)

PDF

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

Theme: Clue symmetry and logic

Rules: Standard Yajilin 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 = 8:30, Master = 12:00, Expert = 24:00

Solution: PDF

PDF

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

Theme: Logical

Rules: Standard Yajilin 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 = 2:30, Master = 3:30, Expert = 7:00

Solution: PDF

PDF

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

Theme: Almost All Two Easy!

Rules: Standard Yajilin 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 = 0:55, Master = 1:10, Expert = 2:20

Solution: PDF

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: TC

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 = 1:00, Master = 1:30, Expert = 3:00

Editor’s Note: Today we add Tom Collyer to our list of Contributing Puzzlemasters. A noted sudoku solver and puzzle author, Tom’s Friday Puzzles have been an online puzzle mainstay for many years — not to be confused with Thomas‘s Friday Puzzle which started around the same time.

Solution: PDF

We will soon begin to regularly post Yajilin puzzles here. Yajilin is a style that is quite different from the other loop styles we have at the moment. Most of those have to do with how a loop travels in small regions. Masyu puzzles, for example, contain clues that require a loop to go straight or turn in specific cells; most of the logic focuses around how to make the loop obey these path instructions. Yajilin is focused more on where a loop travels, which is almost everywhere in the grid. As a variation on other “visit all cells” loop puzzles, the logic in Yajilin revolves around how to get in and out of every part of the grid with only a few cells untouched.

While the style may be familiar, our Yajilin will not look exactly like the Yajilin puzzles you are used to seeing elsewhere. We strongly believe that a wider range of puzzles, and more interesting puzzles, are possible if constructors are allowed to mark some cells as “unused” — neither white nor black. In the standard format, all of these spots would then need arrow clues resulting in excessive and often redundant clues that can subtract from the potential aesthetics or logic of a puzzle. It would simply be impossible to make a standard Yajilin with the curious but pedagogical properties of this example puzzle below.

Increasing the flexibility for the puzzle designer to include known spots that the loop cannot enter seems to meaningfully increase the range of possible Yajilin puzzles. So this is what Grandmaster Puzzles will do with our Yajilin puzzles (although sometimes they may still look “classic”). We hope the change only adds to your enjoyment of this puzzle style.

PDF

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

Theme: Easy as (0,) 1, 2, 3?

Rules: Standard Yajilin 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 = 1:15, Master = 2:30, Expert = 5:00

Solution: PDF

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)

This is a “Franken-Friday” puzzle variation.

Theme: Half Truths

Rules: Variation of Masyu rules. Half of the circles are lying; a lying white circle is actually a black circle and a lying black circle is actually a white circle. The loop must alternate between true circles and lying circles (T-L-T-L-…).

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 = 5:30, Master = 10:00, Expert = 20:00

Solution: PDF