Sudoku Variants Series (124) - Sum to 9 Sudoku
(Published on 12. April 2016, 00:00 by Richard)
Sum to 9
Solve online in F-Puzzles (thx bbutrosghali!)
Place the digits from 1 to 9 in every row, column and 3x3-block. Clues outside the grid indicate the sum of all direct neighbours of the digit 9 in the respective row or column.
This sudoku variant was introduced during the Dutch Sudoku Championship on 10 april 2016. This puzzle was too hard to be used in the Championship because it takes too much time to figure out where to place the first nines.
Solution code: Row 5, followed by column 4.
Comments
on 14. July 2022, 17:01 by Richard
Added link and tag for online solving. Thx bbutrosghali!
on 29. November 2021, 21:20 by snowyegret
can you please clarify the meaning of "direct neighbours". is it the two orthogonally adjacent cells ? for example if the row is 129345678 then that rows clue would be 5 ?
---
Answer: your example is correct. Direct neighbours in a row are the digits direct on the left and direct on the right of the nine; neighbours in a column are the digits direct above and direct below the nine. In case the nine is at the border, there is only one neighbour in that row or column.
on 17. April 2021, 17:15 by bbutrosghali
https://f-puzzles.com/?id=yh9spbe4
on 17. April 2016, 00:22 by zhergan
It was little bit hard to progress for some digits. But this one is clearly a very nice sudoku :)
on 15. April 2016, 14:47 by Realshaggy
A wild guess is, it's not the same people that dislike hard and easy puzzles.
on 15. April 2016, 07:42 by Richard
This puzzle was my first try to make this new variant without givens. I was convinced that should be possible. Although this one turned out to be logical solvable, I realised many players wouldn't be able to find the logic during a championship. For that reason I used it here. There is a little bit of elimination necessary before the first 9 can be placed, but it isn't very hard to find. I have written these steps in a hidden comment.
on 14. April 2016, 21:23 by HaSe
Nicht leicht, aber schon noch vernünftig lösbar.
Und wie immer wunderschön, klasse Rätsel und natürlich die absolut "best series ever".
on 14. April 2016, 08:10 by Statistica
Das war für mich bisher das Schwierigste von den 124. Hat aber Spaß gemacht!
on 13. April 2016, 20:22 by Richard
Obviously some people didn't find the logic, otherwise I can't explain the quick drop from 90 to 82%. Sometimes easy puzzles aren't appreciated, sometimes the hard ones. I don't know what players expect now and than... :-(
on 13. April 2016, 20:20 by Richard
@Hasenvogel: you can determine the first placements of nines by logic, but it takes some time.
on 13. April 2016, 19:51 by Hasenvogel
Nicht eindeutig, musste ausprobieren. Ansonsten witzige Variante
