Two games in one

dodo · Posted: Sun Jun 24, 2007 10:43 am Post subject: Two games in one

Something that strikes me about Sudoku is that it is actually two games in one. Game#1 is the newspaper's Sudoku, and it is played in the space of visible pegs; game#2 is played in the space of remaining candidates, and requires maintenance of those candidates (i.e. an extra sheet of paper, or a computer). Games clearly on the #2 category are probably unsuitable for newspapers, not because they are harder (which they probably are), but because of the extra materials imposed to the player. There is, of course, a gray zone in the middle, since f.i. hidden pairs can be detected by eye in a #1 game.

I wonder if someone can point me to a link where this difference is studied, esp. in the context of problem generation.

wapati · Posted: Mon Jun 25, 2007 2:28 am Post subject:

dodo · Posted: Tue Jun 26, 2007 4:29 pm Post subject:

I wonder, what complications require maintenance of candidates and clearly belong to the #2 zone. Maybe fishes of size greater than 2, or long chains of coloring.

Of course, if you had a perfect memory, you could solve #2's without extra paper nor a computer. X-wings, and even simple pairs, are bound to be forgotten and rediscovered, if they are not filled in in the next few moves, or if you have more than a few to remember. In the end, these imply maintaining candidates (in memory).