Sunday 15 May 2016

Daily League #68: Inside Sudoku and Outside Sudoku

This is the second twin Sudoku. This time it's a combination of Inside and Outside Sudoku. They're pretty similar types, but the solve is still different.

Inside Sudoku first appeared on the US Sudoku Qualification. I thought the idea worked pretty well. I don't remember seeing it anywhere after that. I turned the idea in a Frame Sudoku, which has been repeated numerously, mostly by Richard Stolk.
The construction of the combination took a bit of work. Setting up the opening was pretty easy, but after that it gets a lot trickier. It's hard to pick the right digits that help both puzzles along. I liked the opening and found some points that nicely helped both puzzles along. It was hard to find a way to get both puzzles unique. There were a few situations that wouldn't resolve uniquely and I took a while to figure out how to avoid those.
I think both puzzles turned out nicely. The Outside Sudoku is the easier of the two. You get a lot of simple digits from the opening, while the Inside Sudoku's opening is more of a struggle. Enjoy.

Rules for Sudoku

Inside Sudoku: In this Sudoku digits on the outside indicate that these digits must appear in the 2nd, 3rd or 4th cell in that row or column when looking from that side.

Outside Sudoku: In this Sudoku digits on the outside indicate that these digits must appear in the first three cells in that row or column, when looking from that side.

Click to enlarge


Sunday 1 May 2016

Daily League #67: Edge Sums Sudoku and Frame Sudoku

Possibly this month will feature five Double Trouble Sudokus. I have written two so far, but I don't know if I will be able to write three others in combinations I haven't seen before. But I'm at least going to give it a try.

This week the puzzle can be solved both as an Edge Sums Sudoku and as a Frame Sudoku. I have used them together in a puzzle, but now they're separate puzzles. I tried for a while to get both puzzles to be solvable without any givens. I only had a limited range of sums to work with, which caused some issue. Edge Sums was the hardest to get unique in this combination as Frame Sudoku gives you the option of creating a useful implied sum. Eventually I compromised by putting two givens in the middle. The Edge Sums puzzle is the easier of the two in this set.

Rules for Sudoku

Edge Sums Sudoku:
In this Sudoku numbers on the outside indicate the sum of the first two digits in that row or column, when looking from that side.

Frame Sudoku:
In this Sudoku numbers on the outside indicate the sum of the first three digits in that row or column, when looking from that side.

Click to enlarge