dailysudoku.com

[alanr555]

Several contributions to various fora refer to backtracking or reviewing
what one has done so far.

A computer solution can prepare elaborate and excellent trails to a
solution but what is an easy way to document the solution process
when working manually?

Pencil marks can be used to work towards a solution but once a digit
has been eliminated, how can one know that it was still a possibility
three, six or ten moves previously? Short of taking a snapshot after
each move, one must develop an "audit trail" of some kind.

Do other solvers maintain such a trail?
What tips and tricks are there for working back from a mistake (or even
from a trial/error "stuck" position)?

Alan Rayner BS23 2QT

[tdp]

i'm new to this but i put all possible digits in a square based on the horizontal, vertical and local grid. then i look for anything by itself and fill it in. then i look at a local grid to see if anything can be elminated as creating a forced duplication of a digit

without knowing it my first puzzle solved was a "hard" puzzle. i have since solved a couple others but failed on a "very hard" from last week.

this is terrific fun and i look forward to doing more of them in the future. i don't know the tips and tricks but going at it with a modified algorithm seems the way to go for me.

[tdp]

i use pencil to fill in squares. on things i fill that i'm sure about i put a small dog in the square with the digit. then if i make a mistake and have to backtrack out i only erase things that don't have a dot.