I know perfectly well how to solve these puzzles using logic alone. I also know perfectly well that there is, if you use logic alone, only one solution. I have not now, nor have I ever had, any problem with IJ's point.

However, as I said on another thread, people who haven't yet worked out the all the finer points of logic to enable them to solve the puzzles will, at some point, be tempted to guess and see where it takes them. Having been at that stage a couple or three weeks ago myself, I found I was having to guess one of 2 possible numbers in order to carry on. More often than not, these would lead to a dead end, with duplicates, and I had to re-trace my steps and try the other number to complete the puzzle. On 2 occasions, however, I found that both the numbers that I tried led to a "valid solution" in that each row, column and box contained one of each digit 1 - 9. One of these solutions was the "correct" one, that could have been arrived at had I known how, the other was "incorrect" but still "valid". Once a player discovers the finer points of logic required, he no longer needs to guess, and the issue therefore does not arise again.

Is that clear enough now?

Pappocom - this is what comes of hacking people's posts about and moving them about to create new threads. Other people cannot hope to understand why the "original" post in this thread was posted. As I said before, it's like walking in on a conversation half-way through. By moving the "original" post from its place in the "Trial & Error" thread, it looks as if, at first glance, I am maintaining that your puzzles do not have a unique, logic based solution, particularly if readers either don't bother to follow the post's argument properly or bother to find out where it came from originally. It was a perfectly logical adjunct to the T&E thread. On its own, it does not stand up to scrutiny very well, hence the misunderstanding that has arisen. Some of this misunderstanding is my fault, I guess, as I could not fathom why people did not understand my original premise. It only now occurs to me that, if others did not bother to read where this thread came from and the original discussion on the T&E thread, they can never really understand why I have been so adamant about this. I know where this discussion originated and why I posted it. Others don't.

Lastly, if IJ did not get to read my thoughts on Netiquette, then that is a shame. He surely needs the pointers I posted, otherwise he will end up about as popular as a pork pie in a synagogue