The New Sudoku Players' Forum

[Kindaichi]

Some Sudoku programs like those in handphones and handheld consoles don't have the pencil marking features. Is it possible to solve those hard lvl puzzles without the help of marking?

[Heuresement]

In many cases, yes. I cannot give you a definitive answer as there are many different portable devices, and no one hard level standard. If you would like to know how to solve without marking, then perhaps you could post an example as a response, and if it is possible, someone should be able to let you know how.

You may be also interested to know that solving the puzzles without marking has also been discussed in other threads, eg http://forum.enjoysudoku.com/viewtopic.php?t=3087.

[Jumper]

It seems a different sort of puzzle when solving with no notes. I find it exhilarating. I found a new mental technique to use. It is not a new method, simply a way for me to "see" a bit better. I suspect some minds already do it. I noted that one numeral and one only must be on each of the four outer sides. Obviously a numeral in a corner satisfies two outer rows. Using this concept lets my mind jump from one side to the other rapidly and I have found it helpful sometimes.

[tso]

Generally the hardest puzzles published in most newspapers and similar for the general public sources can be solved without pencilmarks by the reasonably skilled solver. Apparantly, even the hardest can be solved without pencilmarks by the most skilled solver -- see RW's comments in this thread.