Introduction

The rules of this competition were to create a Sudoku puzzle, without any extra rules, constraints or other variations. The puzzle had to have given clues forming a fixed pattern in the grid. Puzzles were submitted and judged anonymously, with three prizes being awarded by myself, and a 4th put to a public vote.

The chosen layout is close to my heart, being very similar to the first ever puzzle I published on this blog back in 2009. Back then I couldn't quite get this working without having to add an extra given digit at R5C5.

Thank you to each of the authors who contributed their entries:

Anuraag Sahay
Florian Wortmann
Gareth Moore - Prize Winner
Jack Lance - Prize Winner
Jiri Hrdina - Prize Winner
Kumaresan R - Prize Winner
Sam Cappleman-Lynes
Sinchai Rungsangrattanakul
tamz29
Tom Collyer
Yoshi Baroshi
Yunus Emre Büyükkale

A printable PDF of the puzzles can be found here: PDF of entries

Prize Winners

Author: Jack Lance
Difficulty: 3/10 [Easy]

Remarks: As soon as I saw this I knew I had a winner on my hands. The symmetry of this puzzle is absolutely stunning with consecutive pairs arranged in Battenberg formation around the grid, attached to another consecutive pair for good measure. However what I find most pleasing about the symmetry is that it doesn't fall into the pastiched trap of a Gurth's Theorem situation where you only get to solve half (or even a quarter) of a puzzle. Crucially with this puzzle different given digits in the grid are not rotational symmetric from other given digits, which breaks the symmetry and ensures the puzzle maintains an interesting, albeit easier solve. Absolutely beautiful - this is the single puzzle from the set that I wish I had written and in my eyes is now *the* definitive puzzle for this layout.

Author: Jiri Hrdina

Difficulty: 3/10 [Easy]

Remarks: This is a wonderfully smooth-solving easy puzzle, setting up the obvious hidden pairs in boxes 2, 4, 6 and 8. These boxes together with box 5 then resolve themselves leaving the corners of the puzzle to be mopped up via some more hidden singles. The sort of highly polished easy puzzle I really appreciate!

Author: Gareth Moore
Difficulty: 5/10 [Medium]

Remarks: This puzzle moved away from an easy level in a very pleasing way, nicely setting up a naked triple half-way through the solve; this set this puzzle apart for me. But don't just take my word for it, one very experienced sudoku solver thought that:

Clearly a favourite. It has a nice solving path, not too easy / not ridiculously hard. ... It would be a good puzzle for the WSC finals or something.

Public Choice Winner

Author: Kumaresan R

Difficulty: 10/10 [Extra Hard]

Remarks: Interestingly my dearest readers plumped for one of the Extra Hard puzzles, which neatly wraps up the set of prizes (I should add I had picked my favourites before I counted the votes - in theory an entry could have won two prizes). It must be said Extra Hard in this case comes with a bit of a health warning - you can use a uniqueness technique to turn this puzzle into a much smoother solve, however knowing that some solvers prefer not to use uniqueness if they can help it, this was how I felt I had to rate the puzzle.

The author had this to say about the puzzle:

Actually it is not hard but an advance technique is involved. Without this technique unique rectangle can be used to complete the puzzle.

Whilst another solver said:

The puzzle I preferred requires a very unusual way of uniqueness, which once found solves the puzzle. Not sure for the 10/10 rating for difficulty since it was an easy spot, but surely 10/10 of cleverness!