Battlefield Sudoku #4: Knights!
(Published on 23. June 2020, 04:08 by Big Tiger)
Standard Sudoku Rules apply to the final numerical layout.
The Battlefield Basics: On this ancient battlefield, 36 armies fought: 9 from each horizontal direction, and 9 from each vertical direction. Each army advanced X cells, with X being the first number at their end of their row or column, and counting the first cell as part of their advance.
Where two opposing armies overlapped, there was a bloody battle and resulting casualties. Where two opposing armies ceased advancing and declared a truce before a battle could ensue, lives were thankfully spared.
The Numbers outside each row and column indicate the sum of either the casualties or the lives spared, but do not indicate whether it was a battle or a truce.
On the puzzle grid, Red Cells indicate all the fields where both a row and a column engaged in battle. Green Cells indicate all the fields where none of the four armies from that row or column ever entered.
For this Battle, Knights have entered the fray! Any two cells a knight's chess move away from each other cannot contain the same number.
*****
Setter's Diary :: June 23, 2020 :: In my fourth installment of the Battlefield rules, I have added Knights which enabled me to remove some of the border numbers. It took me a while to find a working combination of numbers to include that did not reveal too much and render the knights obsolete. I believe I have achieved this, but if someone wants to challenge himself by testing it without the Knights Constraint and report back, I'd be glad to hear the results.
October 22, 2020 :: Thank you to those who took the time to try solving it as if the Knights did not exist and proved that this constraint is indeed necessary for reaching a unique solution!
Solution code: Row 4 then Row 6.
Comments
on 4. September 2020, 05:55 by DiMono
I tried it without the anti-knight constraint. After an hour and 40 minutes, I had most of the outer ring, pairs in box 7, two triples in row 3, and a couple other digits dotted around. Could not make further progress without the anti-knight constraint. Applying it at that point, with the pencilmarks I had, it finished almost immediately. Very nice puzzle.
on 13. July 2020, 10:16 by Willy Wonka
Very enjoyable puzzle! Negative constraints helped me place a few more digits in my attempt to avoid the anti-knight constraint, but I could only find the solution using this constraint. Excellent variant, wonderful setting!
on 26. June 2020, 04:38 by Greg
Fantastic puzzle! the 100% is deserved I guarantee you.
on 26. June 2020, 03:07 by Big Tiger
Wow, the ratings finally accrued for this one and I temporarily sit at 100%! Thank you, all, for finding this one so appealing!
on 25. June 2020, 13:27 by henrypijames
I was thinking about how to illustrate the rules more clearly, and tried something out. Take a look:
https://gist.github.com/henrypijames/828acbc1a4401af5319657bb9cf3aa1f
@Big Tiger: If you like it, feel free to use it (or modify it as you need).
on 25. June 2020, 08:29 by henrypijames
I believe the Red Squares rule is easier to understand if changed to "... *all* the fields that have been entered by all armies from each of the *four* directions." That also put it better in line with the Green Squares rule.
Also, it might be confusing to some that the red/green in your example means something different from the red/green in the puzzle. Better change one of them to a different pair of colors.
**** Out of at least four Battlefield puzzles, everyone's understood it so far. I'm going to leave it as is for now.
on 23. June 2020, 16:17 by marcmees
thanks big tiger for an other nice battle
