dailysudoku.com

[David Bryant]

There have been several posts in this forum about multiple solutions to a well-formed Sudoku puzzle. Sometimes the poster managed to omit one or two numbers from the original puzzle. In other cases the second "solution" was erroneous.

I haven't gone back to verify this, but I think all the erroneous solutions had duplicate numerals in columns, but no duplicates in rows.

Anyway, this got me to thinking. I find it more difficult to review the columns in a completed Sudoku than to review the rows. In other words, I have a harder time focusing on details when I move my eyes up and down, and an easier time when my eyes move left and right. I suppose this is because of the way we write English. Someone who reads a language that's written in columns (like Japanese) might have an easier time inspecting the columns, and a harder time with the rows.

So I tried checking the columns in a completed puzzle by turning the paper sideways and it worked! The numerals were a little harder to recognize because they were lying on their sides, but I still found I could check for duplicates in a column much more quickly this way.

Has anyone else noticed this? dcb

[pseudo coup]

I'm a bean counter and look at columns of numbers for a living. I haven't noticed any difference between horizontal and vertical error recognition. My only expereince with reading has been in English, with some French and Spanish as an adult.