Rules:
Sudoku: Within the thick-bordered 9x9 grid, place the digits 1 to 9 in every row, column, and 3x3 box.
In Order: A digit from 1 to 9 must be placed in each dashed-line cell outside the grid. Digits in those cells give the order in which those digits must appear in the corresponding row or column, but not necessarily next to each other.
Partial Cave: Shade a set of digits from the entire grid such that every instance of those digits is shaded and every instance of other digits is unshaded. Shade the digits in such a way that if you limit the grid at the 9x9 that does not contain the last three columns (i.e. the 9x9 composed of the dotted columns and the six leftmost columns of the thick-bordered grid), all shaded cells are connected orthogonally by other shaded cells to the edge of that 9x9, and the remaining unshaded cells form one orthogonally connected area.
Counting arrows: Digits with arrows give the number of different digits that appear in straight lines in unshaded cells in the indicated directions combined inside the 9x9 denoted above.
Double Japanese Sums: Numbers in the upper side of the puzzle indicate the sums of the digits in groups of shaded and unshaded cells in the corresponding column, in order.
A single ? represents a single digit from 1 to 9. Combined with other digits, it can also be 0, as long as it is not the leading digit. ?? represents some number which is greater than 9. * represents any number of sets of consecutive cells with arbitrary sums including no cells at all.
Some clarifications about the rules.
This in an example of how digits in dotted cells work:
Solution code: Row 1, left to right, including the outside clues (12 digits).
on 7. April 2024, 22:45 by Madoka42
Didn't plan to spend so much time on it, but was really nice and well worth.
- thank you so much! Yeah, it's a tough puzzle! - damasosos92
on 6. February 2024, 23:25 by yttrio
Very fun (and hard) puzzle! The cave shading led to some particularly interesting logic.
on 6. February 2024, 23:24 by jwsinclair
This is a great puzzle, and among the toughest I've ever solved. Enjoyed being its first "victim", and I'm glad you're letting others share in the experience :)
on 6. February 2024, 23:21 by zzw
Awesome puzzle, loved it! The cave shading rules work very well, and those arrows are certainly quite satanic.
on 6. February 2024, 23:21 by Myxo
Very fun puzzle! I really enjoyed it.