Puzzle No. 498: Next To Nine Sudoku

This was posted in the Daily League last week but I didn’t get the time to post it here. I’ll finish up the recaps today too. I think.

Rules – Follow regular Sudoku rules. Additionally, the clues outside the grid indicate the numbers to be
placed in the cells before and after the cell containing 9 in the corresponding direction.

Enjoy!

NextTo9

Puzzle No. 497: Odd-Even Count Sudoku [Daily League]

The WSC/WPC Recaps will resume tomorrow.

Remember that you can solve the puzzles from the League online on the Sudokucup Guest League page with a 24h delay.

Rules – Follow regular Sudoku rules. Additionally, An even number placed in a cell with a circle indicates the number of even numbers placed in the surrounding 8 cells. An odd number placed in a cell with a circle indicates the number of odd numbers placed in the surrounding cells. Numbers placed in cells without a circle may have either of these properties.

Enjoy!

OECount

Puzzle No. 456 : Sudoku +/-4 [Daily League]

More of the practice puzzles I wrote for Team India. This variation was in the WPC and IS pretty puzzly, but I’m pressed for time and this solved the purpose of a Sudoku post.

Remember that you can solve the puzzles from the League online on the Sudokucup Guest League page with a 24h delay. However, I spoke to Karel and chances are this one might not be interface friendly. Do check in tomorrow if you want to though, just in case.

Rules – 

Enter whole numbers between -4 and +4, inclusive, into the grid so that each row, column and region contains all possible numbers exactly once. Clues outside the grid indicate the sum of all numbers that appear between the clue and the cell containing zero in that row/column. Some cells already contain a number. However, the signs for these clues are not indicated, it is part of the puzzle to determine whether they are positive or negative values.

Rated – Hard.

Enjoy!

P456

P456

Puzzle No. 440, 441 : Tapa [Touch and Go]

I’ll just quickly link to a few of my contributions to the recent Czech Team Sudoku and Puzzle Championships.

1. I co-authored a Sudoku team round with Tom Collyer. The round has easy classics, that give some digits which need to be transferred to harder variants. The Weighted Killer, the Outside or Skyscraper, the Rossini and the Battenburg are all written by me. They are all uniquely solvable, without the transferred digits, but obviously, the transferring makes them easier. This Sudoku round is the 6th round, and can be found in PDF numbers 28 and 29 in the Sunday tab of the above link.

2. I wrote two team puzzles, one being an interconnected wall puzzle, a combination of LITS, Nurikabe and Tapa. This puzzle has two versions. The original version included determining where the part-grids go as well as solving them. Based on testing times, I decided to make it easier and gave the positioning of the 9 grids at the start itself. The detailed wall rules and the actual competition puzzle can be found on the Sunday tab of the above link, it is the 6th Puzzle round, which is PDF numbers 35 and 36. There are English rules there too. The original version of the puzzle, with just the layout given and some added logic required in placing the part-grids correctly, is given below.

OriginalWall

3. The second team puzzle was a Loop puzzle. It is a combination of 4 loop types, a Masyu, a Yajilin, a Simple Loop and a Country Road. There’s an added rule that there are certain shaded cell positions given where the loop segment behaviour is exactly the same for all 4 grids. This can be found on the Saturday tab, it is the 2nd puzzle round, PDF numbers 16, 17 and 18.

To today’s puzzles now. I came up with this variant today, and liked it enough to use it in two puzzles. I didn’t really check if the variant exists already, but I can’t remember solving one with these rules.

Rules – Follow regular Tapa Rules. Additionally, no dead-end can ever be a part of a checkerboard pattern. A dead-end is a shaded cell with just one orthogonally adjacent shaded cell, and a checkerboard pattern is a 2×2 area of alternating shaded and unshaded squares. Note : The clue cells are also considered as unshaded cells for the checkerboard pattern.

Rated – Medium (the first one’s on the easy side and the next one’s harder)

Enjoy!

P440

P440

P441

P441

Puzzle No. 420 : Heyawacky

Oh btw, I placed 2nd in the Times Sudoku Championship National finals here in India, with Rishi Puri winning it, Rohan Rao coming in at 3rd and Jaipal Reddy completing the top 4.

There were a few articles covering us, I’ll just post the ones related to the finals – here (Times of India, 1st page of Times Sport)  and here.

The rounds themselves were nicely organized by LMI, with the 1st round being a sprint round of 6x6s (classics and mostly variants), the 2nd round just 9×9 Classics, the 3rd round had 9×9 variants and the 4th round was a piece-placement type mechanical round. It was all great fun, especially since I was competing against 2 of the best Sudoku solvers in the world in Rishi and Rohan. I goofed up bad on the 1st round and so did Rohan (even worse). Rishi was super consistent throughout the 4 rounds. Rohan made up a lot of his deficit in round 2 and a little more in round 3, and I had an excellent round 3, meaning we were all really close come the final round, which didn’t have much separation unless one of us didn’t finish it at all. We all finished, and so there wasn’t much change by that round. In the end, I tied with Rohan, but the 3rd round was prioritized and since that was the round where I excelled, I ranked ahead of him. Rishi was a little further ahead.

So to the puzzle. This Heyawacky has quite a tricky start. After the tricky start, there isn’t a whole lot to it, but still a good flow to the end I think.

Heyawacky rules.

Rated – Medium.

Enjoy!

P420

P420

Puzzle No. 418 : Domino Sudoku [Daily League]

Firstly, PDFs!

Week 27.

Week 28.

Today’s Sudoku is just an experiment, that I think is neither great nor bad. After last week’s challenge, this should be pretty easy.

Rules – Place a digit from 1-8 in each cell of the grid so that every row, column and thickly outlined 2×4 box contain the digits 1-8. Also, in each 2×4 box, there must be 4 distinct dominos (1×2 tiles). The distinctions are – Vertical+Odd, Horizontal+Odd, Vertical+Even, Horizontal+Even. In other words, there should be two dominos of each parity, one horizontal and one vertical.

Enjoy!

P418

P418

Puzzle No. 415 : Repeated Neighbours Sudoku [Daily League]

Firstly, PDFs!

Week 25.

Week 26.

Remember that you can solve the puzzles from the League online on the Sudokucup Guest League page with a 24h delay.

Today’s Sudoku is quite tough I think. It has a really narrow path with some really tricky deductions on the way. Still, I like the logic as well as the appearance I got working here.

Rules – Follow regular Sudoku rules. Additionally, each shaded cell must have repeating orthogonal neighbours (neibhbours sharing an edge). White cells must have distinct orthogonal neighbours.

Enjoy!

P415

P415