Coast to Coast
Solve online in Penpa+ (thx Nick Smirnov!)
Place the digits from 1 tot 9 in every row, column and 3x3-block. The digits outside the grid are in mirrored position in the first three cells from the left and from the right (if one digit is in the second cell from the left, the other digit has to be in the second cell from the right).
Solution code: Column 3, followed by column 7
on 14. July 2022, 10:46 by Richard
Added link and tag for online solving. Thx Nick!
on 19. December 2020, 19:25 by Nick Smirnov
Penpa:
https://git.io/JLuwm
on 13. September 2020, 23:22 by SudokuExplorer
Interesting concept! Quite tough for me.
on 26. March 2020, 16:08 by Circleconstant314
@cdwg2000
OK, thanks! I thought they could appear in the middle box, i.e. say for row 4 that the 7 and the 8 could go in positions 5 and 6 of that row, but now I know. Thank you!
on 26. March 2020, 14:21 by cdwg2000
@Circleconstant314
The external reminder numbers must appear in the first three and the last three mirror positions, such as: XY means C1 = X, C9 = Y or C2 = X, C8 = Y or C3 = X, and C7 = Y.
on 26. March 2020, 13:11 by Circleconstant314
I'm trying to solve this but the formulations for the constraint have me confused. Is it necessary that the clued digits appear in the first three cells of the row, or could they not appear there?
on 7. January 2019, 08:51 by Richard
@lubosh: you already submitted the solution for this puzzle in november 2016. :-)
on 7. November 2016, 14:25 by ohm0123
It's hard. uu.
on 14. April 2015, 18:52 by CHalb
Quite amazing that this concept art leads to a really good puzzle.
on 14. April 2015, 11:29 by Statistica
Hab mich schwer getan... Optisch mal wieder ein Genuss!