Years ago I learnt lateral thinking and found it incredibly useful, literally allowing me a higher dimension of thought. It was clear it didn't come naturally and if I stopped doing it for a few days I'd lose it and need to start again. I'm still not sure I remember much about it but can summarise a few points I do remember.

Firstly it means not doing the obvious in any situation. It often involves doing the opposite to it, freeing the bounds of logic but then having to learn a completely new and far more helpful albeit complicated version. It also means thinking of indirect causes which are often far more influential than the clear ones. One simple example I do remember was putting yourself in your opponents position and thinking like them, whether in life or sport.

I wanted to catch up on all the principals online as if I wrote them down I lost them long ago and found barely a thing about it. Despite its power it seems to have become a lost art and not even sure I may now use a little of it without realising it as used it for so long. Does anyone else know about it and can present the rules fairly easily?

I don't know of anything written, rules and such...However, I TRY to always look from both sides. I deal with the public, and sometimes it can be a challenge. If you think from their side, understanding comes easier...Usually!

You made me look again! Two websites have appeared since earlier, this one has summarised them as Edward De Bono (who I now remember coined the phrase) laid them out, but I was taught a far simplified version.

lateral thinking rules

The provocation list refers to much of what I learnt and is far more powerful than you'd think once you start using it. It does include a few specific things I mentioned like reversal, which you use as well and I did manage to remember accurately. I must get it down again in an organised way and simplify it as it means you can get a step beyond any situation you can without it.

Unless you're lucky enough to think like that naturally (and I doubt many do) it's like learning to juggle but well worth it. Best to learn one trick at a time before the next one, I did it as a whole approach which is probably what made it so hard to hold on to.

Seems to be somewhat based on brainstorming - just coming up with ideas without judgeing them initially. A way of allowing the brain to jump the tracks of the old tired ideas, and see new approaches. I could see this being very useful.

I've done this for years and taught it a little, too. Students don't really trust it too much though and the less able are left behind by the ideas behind it.
If you can get an able student to take the ideas on board the results can be amazing.

Glad to hear it's still going and especially being disseminated as well. It is complex and will only appeal to people who can work at a level beyond the normal logic but very helpful for those who can. It can interrupt a repetitive thought pattern and also allow new angles you'd never have opened up otherwise.

Once I saw a few demonstrations of it recently I got most of it back again, and as well as simple reversals (ie what would it be like in the other person's place for instance) there's the opportunity cost question, ie what is this thing stopping from happening (rather than what it's actually doing), and looking for apparently unrelated causes of results rather than ones you can see or work out directly. In Big Brother they had a task room full of activities but the only clue was the meter saying how close they were to passing. The actual requirement was to all leave the room at once, and within the time allowed someone worked it out with about half the time to go.

Once you have a complete set of methods and use them regularly you can bypass many apparently impossible tasks and puzzles and appear far more intelligent than you actually are as well

I do not know how long it has been around, but we now teach "6 Thinking Hats" , another de Bono concept, which gives us the mind tools to make decisions. There are courses for quite young children. Rather interesting.