Everything about Sudoku that doesn't fit in one of the other sections

Let's see if the solvers in this forum can tell quality hand made puzzles from computer generated puzzles -- that have identical clue placement.

I've chosen 18 puzzles from a single source. I've generated puzzles by several different methods with matching masks and presented them in pairs -- exactly one is handmade, exactly one is computer generated. Some attempt has been made to roughly match solving charactoristics in each pair of puzzles. The puzzle pairs are presented *roughly* in order of difficulty -- the easiest nearer the top, the hardest nearer the bottom. None of these puzzle require any advanced tactics -- all can be solved with some combination of naked and hidden sets, locked candidates and singles. These are paper-and-pencil level puzzles.

Solve as many or as few as you please as long as you solve them in pairs. Post your conclusions here -- which puzzles you think are handmade, why, how sure you are, whatever. Be as verbose or terse as you wish. I'll post the answer key when activity has died down -- assuming there is any.

NOTE: The 14th puzzle has been left out as I was unable to generate a 20-clue matching puzzle.

Code: Select all
`===================================Puzzle number 1a+-------+-------+-------+| . . . | . . 3 | 6 5 1 | | . . 2 | . . . | . . 4 | | . . 3 | 1 6 . | . . 2 | +-------+-------+-------+| . 5 7 | 2 . . | . . 8 | | . . . | 4 . 1 | . . . | | 4 . . | . . 9 | 3 6 . | +-------+-------+-------+| 3 . . | . 5 2 | 1 . . | | 1 . . | . . . | 7 . . | | 2 6 4 | 9 . . | . . . | +-------+-------+-------+Puzzle number 1b+-------+-------+-------+| . . . | . . 7 | 8 9 6 | | . . 4 | . . . | . . 1 | | . . 7 | 5 1 . | . . 2 | +-------+-------+-------+| . 3 8 | 2 . . | . . 4 | | . . . | 6 . 9 | . . . | | 1 . . | . . 4 | 6 2 . | +-------+-------+-------+| 9 . . | . 4 5 | 1 . . | | 5 . . | . . . | 7 . . | | 7 4 1 | 3 . . | . . . | +-------+-------+-------+===================================Puzzle number 2a+-------+-------+-------+| . . . | . 5 . | . 2 . | | 4 3 . | 9 . 1 | . . 7 | | . 8 . | 4 . 2 | . 1 . | +-------+-------+-------+| . 7 . | . 3 . | 8 5 . | | . . . | 5 . 6 | . . . | | . 1 3 | . 7 . | . 9 . | +-------+-------+-------+| . 5 . | 8 . 3 | . 4 . | | 2 . . | 7 . 5 | . 3 6 | | . 9 . | . 1 . | . . . | +-------+-------+-------+Puzzle number 2b+-------+-------+-------+| . . . | . 9 . | . 4 . | | 1 4 . | 5 . 2 | . . 7 | | . 3 . | 6 . 4 | . 8 . | +-------+-------+-------+| . 9 . | . 3 . | 4 7 . | | . . . | 7 . 8 | . . . | | . 2 5 | . 6 . | . 3 . | +-------+-------+-------+| . 6 . | 2 . 7 | . 1 . | | 2 . . | 9 . 3 | . 6 8 | | . 7 . | . 5 . | . . . | +-------+-------+-------+===================================Puzzle number 3a+-------+-------+-------+| . 2 . | 8 . . | . 1 . | | 4 7 . | . . . | . 2 9 | | . . . | 2 5 9 | . . . | +-------+-------+-------+| . . 1 | . . . | 8 . 3 | | . 6 . | . . . | . 9 . | | 8 . 5 | . . . | 2 . . | +-------+-------+-------+| . . . | 3 6 8 | . . . | | 9 8 . | . . . | . 3 7 | | . 4 . | . . 1 | . 8 . | +-------+-------+-------+Puzzle number 3b+-------+-------+-------+| . 3 . | 4 . . | . 2 . | | 5 7 . | . . . | . 4 6 | | . . . | 6 8 1 | . . . | +-------+-------+-------+| . . 4 | . . . | 5 . 2 | | . 1 . | . . . | . 7 . | | 7 . 3 | . . . | 8 . . | +-------+-------+-------+| . . . | 1 2 6 | . . . | | 6 4 . | . . . | . 1 7 | | . 2 . | . . 7 | . 5 . | +-------+-------+-------+===================================Puzzle number 4a+-------+-------+-------+| 3 . . | . 7 . | . . 4 | | . 1 . | 2 . 6 | . 7 . | | . . 4 | . . . | 5 . . | +-------+-------+-------+| . 3 1 | . . . | . 4 . | | 8 . . | . . . | . . 3 | | . 6 . | . . . | 7 2 . | +-------+-------+-------+| . . 5 | . . . | 2 . . | | . 2 . | 6 . 5 | . 1 . | | 7 . . | . 3 . | . . 8 | +-------+-------+-------+Puzzle number 4b+-------+-------+-------+| 9 . . | . 3 . | . . 7 | | . 8 . | 5 . 6 | . 1 . | | . . 2 | . . . | 6 . . | +-------+-------+-------+| . 4 6 | . . . | . 2 . | | 7 . . | . . . | . . 9 | | . 2 . | . . . | 5 8 . | +-------+-------+-------+| . . 7 | . . . | 3 . . | | . 1 . | 2 . 3 | . 7 . | | 3 . . | . 5 . | . . 8 | +-------+-------+-------+===================================Puzzle number 5a+-------+-------+-------+| 1 . 2 | . . . | 3 . 4 | | . . . | 7 . 8 | . . . | | 8 . 5 | . . . | 6 . 1 | +-------+-------+-------+| . 6 . | . 8 . | . 9 . | | . . . | 9 . 7 | . . . | | . 5 . | . 2 . | . 1 . | +-------+-------+-------+| 9 . 6 | . . . | 2 . 5 | | . . . | 4 . 3 | . . . | | 3 . 8 | . . . | 7 . 9 | +-------+-------+-------+Puzzle number 5b+-------+-------+-------+| 7 . 1 | . . . | 6 . 4 | | . . . | 9 . 6 | . . . | | 8 . 5 | . . . | 9 . 3 | +-------+-------+-------+| . 2 . | . 5 . | . 9 . | | . . . | 6 . 1 | . . . | | . 1 . | . 4 . | . 7 . | +-------+-------+-------+| 9 . 7 | . . . | 2 . 5 | | . . . | 8 . 3 | . . . | | 4 . 2 | . . . | 8 . 1 | +-------+-------+-------+===================================Puzzle number 6a+-------+-------+-------+| 4 7 . | . . 3 | . 6 . | | . . . | 2 . . | 4 . 1 | | . . 2 | . . 4 | . 9 . | +-------+-------+-------+| . 2 . | . 4 . | . . 7 | | . . 7 | . . . | 3 . . | | 1 . . | . 6 . | . 8 . | +-------+-------+-------+| . 1 . | 6 . . | 8 . . | | 9 . 6 | . . 8 | . . . | | . 8 . | 7 . . | . 1 9 | +-------+-------+-------+Puzzle number 6b+-------+-------+-------+| 8 9 . | . . 6 | . 1 . | | . . . | 5 . . | 4 . 2 | | . . 2 | . . 3 | . 5 . | +-------+-------+-------+| . 3 . | . 8 . | . . 1 | | . . 4 | . . . | 2 . . | | 7 . . | . 4 . | . 8 . | +-------+-------+-------+| . 2 . | 1 . . | 6 . . | | 5 . 3 | . . 9 | . . . | | . 4 . | 3 . . | . 7 9 | +-------+-------+-------+===================================Puzzle number 7a+-------+-------+-------+| 2 . 6 | 4 . . | 5 . 9 | | . 7 . | . 6 . | . . . | | . . . | 3 . 7 | . . . | +-------+-------+-------+| 3 . 9 | . . . | 4 . . | | . 4 . | . 9 . | . 3 . | | . . 2 | . . . | 8 . 5 | +-------+-------+-------+| . . . | 6 . 9 | . . . | | . . . | . 2 . | . 4 . | | 8 . 4 | . . 3 | 1 . 2 | +-------+-------+-------+Puzzle number 7b+-------+-------+-------+| 1 . 7 | 8 . . | 3 . 4 | | . 5 . | . 1 . | . . . | | . . . | 2 . 3 | . . . | +-------+-------+-------+| 7 . 3 | . . . | 2 . . | | . 4 . | . 5 . | . 1 . | | . . 5 | . . . | 9 . 7 | +-------+-------+-------+| . . . | 6 . 8 | . . . | | . . . | . 7 . | . 8 . | | 2 . 6 | . . 1 | 7 . 3 | +-------+-------+-------+===================================Puzzle number 8a+-------+-------+-------+| 4 . . | . 1 . | . . 7 | | . . . | 2 . 3 | . . . | | . . 8 | . . . | 2 . . | +-------+-------+-------+| . 4 . | . 2 . | . 5 . | | 5 . . | 8 . 6 | . . 9 | | . 1 . | . 7 . | . 3 . | +-------+-------+-------+| . . 2 | . . . | 5 . . | | . . . | 1 . 5 | . . . | | 3 . . | . 9 . | . . 8 | +-------+-------+-------+Puzzle number 8b+-------+-------+-------+| 3 . . | . 5 . | . . 7 | | . . . | 4 . 2 | . . . | | . . 8 | . . . | 1 . . | +-------+-------+-------+| . 2 . | . 9 . | . 4 . | | 7 . . | 2 . 1 | . . 9 | | . 4 . | . 3 . | . 6 . | +-------+-------+-------+| . . 3 | . . . | 2 . . | | . . . | 9 . 6 | . . . | | 1 . . | . 7 . | . . 5 | +-------+-------+-------+===================================Puzzle number 9a+-------+-------+-------+| 9 . . | . . 7 | 4 . . | | . 3 . | . 6 . | . 7 . | | 1 . . | . . . | 8 . . | +-------+-------+-------+| . 4 . | . . 9 | . . . | | . . 1 | . . . | 6 . . | | . . . | 2 . . | . 8 . | +-------+-------+-------+| . . 2 | . . . | . . 4 | | . 7 . | . 1 . | . 3 . | | . . 8 | 3 . . | . . 9 | +-------+-------+-------+Puzzle number 9b+-------+-------+-------+| 6 . . | . . 2 | 1 . . | | . 1 . | . 8 . | . 4 . | | 2 . . | . . . | 9 . . | +-------+-------+-------+| . 2 . | . . 7 | . . . | | . . 5 | . . . | 3 . . | | . . . | 6 . . | . 5 . | +-------+-------+-------+| . . 6 | . . . | . . 7 | | . 4 . | . 3 . | . 8 . | | . . 3 | 9 . . | . . 5 | +-------+-------+-------+===================================Puzzle number 10a+-------+-------+-------+| 1 3 . | . . . | . . 6 | | . 6 . | . . 4 | . . . | | . . . | 9 . 8 | . . 7 | +-------+-------+-------+| . . 3 | 7 . . | 5 4 . | | . . . | . . . | . . . | | . 4 7 | . . 3 | 2 . . | +-------+-------+-------+| 6 . . | 2 . 9 | . . . | | . . . | 1 . . | . 5 . | | 2 . . | . . . | . 8 9 | +-------+-------+-------+Puzzle number 10b+-------+-------+-------+| 7 9 . | . . . | . . 3 | | . 6 . | . . 7 | . . . | | . . . | 6 . 1 | . . 2 | +-------+-------+-------+| . . 5 | 2 . . | 4 6 . | | . . . | . . . | . . . | | . 3 9 | . . 8 | 7 . . | +-------+-------+-------+| 4 . . | 5 . 9 | . . . | | . . . | 8 . . | . 4 . | | 5 . . | . . . | . 8 1 | +-------+-------+-------+===================================Puzzle number 11a+-------+-------+-------+| . . 3 | 5 . . | 4 . . | | . 1 . | . 7 . | . 6 . | | . 8 . | . 9 . | . . 7 | +-------+-------+-------+| . . 6 | . . . | . . 3 | | . 7 . | . . . | . 8 . | | 5 . . | . . . | 9 . . | +-------+-------+-------+| 8 . . | . 4 . | . 5 . | | . 6 . | . 2 . | . 4 . | | . . 9 | . . 6 | 8 . . | +-------+-------+-------+Puzzle number 11b+-------+-------+-------+| . . 6 | 8 . . | 2 . . | | . 8 . | . 4 . | . 7 . | | . 3 . | . 9 . | . . 5 | +-------+-------+-------+| . . 7 | . . . | . . 4 | | . 1 . | . . . | . 5 . | | 4 . . | . . . | 8 . . | +-------+-------+-------+| 7 . . | . 5 . | . 3 . | | . 2 . | . 8 . | . 1 . | | . . 1 | . . 9 | 6 . . | +-------+-------+-------+===================================Puzzle number 12a+-------+-------+-------+| 8 . . | . 2 3 | . 9 4 | | 3 2 . | . . 1 | 6 5 . | | . 1 . | . . . | . . . | +-------+-------+-------+| 7 4 . | . . . | . . . | | 6 . . | . . . | . . 7 | | . . . | . . . | . 4 9 | +-------+-------+-------+| . . . | . . . | . 3 . | | . 9 6 | 5 . . | . 8 2 | | 4 3 . | 2 9 . | . . 5 | +-------+-------+-------+Puzzle number 12b+-------+-------+-------+| 4 . . | . 9 3 | . 5 1 | | 2 9 . | . . 6 | 3 4 . | | . 8 . | . . . | . . . | +-------+-------+-------+| 6 3 . | . . . | . . . | | 9 . . | . . . | . . 6 | | . . . | . . . | . 8 7 | +-------+-------+-------+| . . . | . . . | . 9 . | | . 6 9 | 3 . . | . 1 5 | | 3 4 . | 7 5 . | . . 2 | +-------+-------+-------+===================================Puzzle number 13a+-------+-------+-------+| . . . | . . 6 | 4 9 . | | . . . | . 2 . | . . 3 | | . . 5 | . . 8 | . . 2 | +-------+-------+-------+| . . . | 7 . . | 6 . 5 | | . 2 . | . . . | . 8 . | | 3 . 4 | . . 9 | . . . | +-------+-------+-------+| 4 . . | 9 . . | 1 . . | | 8 . . | . 3 . | . . . | | . 5 6 | 2 . . | . . . | +-------+-------+-------+Puzzle number 13b+-------+-------+-------+| . . . | . . 3 | 8 5 . | | . . . | . 8 . | . . 2 | | . . 3 | . . 1 | . . 4 | +-------+-------+-------+| . . . | 9 . . | 4 . 5 | | . 6 . | . . . | . 3 . | | 7 . 2 | . . 8 | . . . | +-------+-------+-------+| 8 . . | 3 . . | 7 . . | | 1 . . | . 6 . | . . . | | . 7 9 | 4 . . | . . . | +-------+-------+-------+===================================There is no number 14. I was unable to get a computer program to create a puzzle matching the 20-clue puzzle in the 14th spot.===================================Puzzle number 15a+-------+-------+-------+| . . 1 | . 3 4 | 6 . . | | . . . | 9 . . | . . . | | 5 . . | 6 . . | . . 7 | +-------+-------+-------+| 4 . . | . . . | 5 6 . | | 9 . . | . . . | . . 8 | | . 3 2 | . . . | . . 1 | +-------+-------+-------+| 8 . . | . . 9 | . . 4 | | . . . | . . 5 | . . . | | . . 7 | 1 2 . | 3 . . | +-------+-------+-------+Puzzle number 15b+-------+-------+-------+| . . 9 | . 8 6 | 4 . . | | . . . | 4 . . | . . . | | 1 . . | 2 . . | . . 5 | +-------+-------+-------+| 3 . . | . . . | 5 9 . | | 2 . . | . . . | . . 1 | | . 6 4 | . . . | . . 8 | +-------+-------+-------+| 7 . . | . . 5 | . . 2 | | . . . | . . 9 | . . . | | . . 8 | 7 3 . | 6 . . | +-------+-------+-------+===================================Puzzle number 16a+-------+-------+-------+| . . . | . . . | . 3 1 | | 8 . 6 | . . 4 | . . . | | . 7 . | . 5 . | 4 . . | +-------+-------+-------+| . . 4 | . . 1 | . . 7 | | . 8 . | . . . | . 5 . | | 6 . . | 9 . . | 8 . . | +-------+-------+-------+| . . 1 | . 9 . | . 8 . | | . . . | 4 . . | 7 . 2 | | 5 3 . | . . . | . . . | +-------+-------+-------+Puzzle number 16b+-------+-------+-------+| . . . | . . . | . 4 7 | | 3 . 7 | . . 1 | . . . | | . 8 . | . 2 . | 6 . . | +-------+-------+-------+| . . 3 | . . 8 | . . 2 | | . 6 . | . . . | . 7 . | | 5 . . | 7 . . | 1 . . | +-------+-------+-------+| . . 6 | . 9 . | . 3 . | | . . . | 6 . . | 5 . 1 | | 4 1 . | . . . | . . . | +-------+-------+-------+===================================Puzzle number 17a+-------+-------+-------+| . . 3 | . . . | 2 . . | | . . . | 4 9 1 | . . . | | 7 . . | . . . | . . 9 | +-------+-------+-------+| . 2 . | . 7 . | . 8 . | | . 7 . | 6 . 2 | . 3 . | | . 5 . | . 8 . | . 9 . | +-------+-------+-------+| 4 . . | . . . | . . 1 | | . . . | 8 6 9 | . . . | | . . 2 | . . . | 5 . . | +-------+-------+-------+Puzzle number 17b+-------+-------+-------+| . . 1 | . . . | 5 . . | | . . . | 2 7 3 | . . . | | 4 . . | . . . | . . 6 | +-------+-------+-------+| . 8 . | . 9 . | . 1 . | | . 5 . | 1 . 2 | . 7 . | | . 4 . | . 8 . | . 3 . | +-------+-------+-------+| 9 . . | . . . | . . 7 | | . . . | 6 1 4 | . . . | | . . 6 | . . . | 4 . . | +-------+-------+-------+===================================Puzzle number 18a+-------+-------+-------+| . . 5 | . . . | 8 . . | | 9 . . | 3 . 2 | . . . | | . 7 . | . 5 . | . 1 . | +-------+-------+-------+| . 4 . | 9 . . | . . 2 | | 6 . . | . . . | . . 3 | | 8 . . | . . 6 | . 4 . | +-------+-------+-------+| . 3 . | . 2 . | . 5 . | | . . . | 8 . 1 | . . 6 | | . . 4 | . . . | 7 . . | +-------+-------+-------+Puzzle number 18b+-------+-------+-------+| . . 5 | . . . | 9 . . | | 7 . . | 2 . 4 | . . . | | . 9 . | . 6 . | . 8 . | +-------+-------+-------+| . 1 . | 3 . . | . . 8 | | 4 . . | . . . | . . 2 | | 6 . . | . . 7 | . 1 . | +-------+-------+-------+| . 3 . | . 5 . | . 2 . | | . . . | 8 . 6 | . . 5 | | . . 7 | . . . | 1 . . | +-------+-------+-------+===================================`
tso

Posts: 798
Joined: 22 June 2005

Mmmhh, this reminds me on discussions, if analog or digital music players are better, mostly without having the possibility to compare (and there is no winner up to day). You made me curious
ravel

Posts: 998
Joined: 21 February 2006

tso wrote:Let's see if the solvers in this forum can tell quality hand made puzzles from computer generated puzzles -- that have identical clue placement.

I've chosen 18 puzzles from a single source. I've generated puzzles by several different methods with matching masks and presented them in pairs -- exactly one is handmade, exactly one is computer generated.

I mostly approve of this test, in the fairness sense. One thing I would point out is that humans would tend to make patterns (visual) and that allowing computers (forcing them) to copy does taint the test a bit.

I would say in general, humans will make patterns that they like (for whatever reason), humans will not actually be random in assigning numbers and humans will place more clues (as in, never create a 17).

I'd slightly prefer that the computer puzzles have the same number of clues and similar symmetry, rather than match the pattern.

I do think that this test is interesting!
fermat

Posts: 105
Joined: 29 March 2006

The point if the comparision is to see if there is a qualitive difference in the solving of quality handmade versus machine made. If they don't have the same clue pattern, in some cases it only takes a glance to recognize which is which. Also, it may be that a perceived solving quality is really tied to the clue pattern, not to the composer's artistry.

If we do another comparison test, it will be Pappocom puzzles verus quality handmade -- similar symmetry and number of clues, but by necessity, they will not have the same clue patterns.
tso

Posts: 798
Joined: 22 June 2005

i didn't give it a lot of thought, more sort of gut reaction but these are the puzzles i think are handmade:
1 b
2 a
3 a
4 a
5 b
6 b
7 b
8 a
9 b
10 a
11 b
12 a
13 b
15 a
16 b
17 b
18 b
ab

Posts: 451
Joined: 06 September 2005

My answers are not very certain.

01-a H
02-b H
03-b H
04-b H
05-a H
06-a H
07-b H
08 No guess
09-a H
10 No guess
11 No guess
12-b H
13-a H
15-a H
16-a H
17-b H
18-a H
fermat

Posts: 105
Joined: 29 March 2006

ravel wrote:Mmmhh, this reminds me on discussions, if analog or digital music players are better, mostly without having the possibility to compare (and there is no winner up to day). You made me curious

Hmm? Analog is so superior, in music.

You cannot compare because digital has lost information. Ok, players may only matter a bit. Analog recorders rock.
fermat

Posts: 105
Joined: 29 March 2006

My generator uses exactly the same techniques to generate a puzzle as it does to solve one. So given that it can solve a handmade puzzle, theoretically it could also have produced that puzzle. Arguably though it can also produce many other valid puzzles that maybe a puzzle setter would disregard.
ab

Posts: 451
Joined: 06 September 2005

ab wrote:My generator uses exactly the same techniques to generate a puzzle as it does to solve one. So given that it can solve a handmade puzzle, theoretically it could also have produced that puzzle. Arguably though it can also produce many other valid puzzles that maybe a puzzle setter would disregard.

Your second sentence does not follow logically from your first. I can read any novel -- this does not imply I can could have written Great Expectations.

Still, one could write a generator that, given unlimited time, would create all possible puzzles -- but then you have a 10000 monkeys situation. Someone or something must sift through and find those that match closely the qualities shared with human-made puzzles -- if these qualities exist.
tso

Posts: 798
Joined: 22 June 2005

your comparison doesn't really hold up tso! Given certain solving strategies there are a finite number of sudoku puzzles, albeit very large. My solver randomly creates one of them so there is a 1 in a very large number chance that it will create one that has appeared in the Guardian for instance. I don't think you could say there is a finite number of possible novels, you could always add an extra word/paragraph/page/chapter etc.
ab

Posts: 451
Joined: 06 September 2005

ab wrote:My generator uses exactly the same techniques to generate a puzzle as it does to solve one. So given that it can solve a handmade puzzle, theoretically it could also have produced that puzzle. Arguably though it can also produce many other valid puzzles that maybe a puzzle setter would disregard.

That is actually the point.

Yes, we are all aware that a computer could have generated any given puzzle.

Human puzzle creators tend to have some discernable pattern, a flavour, if you will.

Computer output will not, unless filtered.
fermat

Posts: 105
Joined: 29 March 2006