mgoetze: I believe that it is important not to explain too much at once. I see many beginners struggling with concepts such as "eyes" and "territory" before they have even played their second game. Why the complications? Just explain the rule of alternation and the rule of capture, then say that (for now) the objective is to have more stones on the board at the end than your opponent. (The group tax won't really matter.) Then give them a handicap and just play. One of the wonderful things about go is that concepts such as life & death are nothing but a consequence of some very simple rules... why make the game seem more complicated than it is? After 2 games or so, explain the ko rule... and go right on to playing another. Also, I try to discourage beginners (as nicely as possible) from thinking too long... the fact of the matter is, they're going to be thinking about all the wrong things, on time that would be much better spent actually playing.
Though I prefer territory scoring, nobody should start with it. Let's put away with our preconception. Rather start as simple as possible. First tell'm the aim of the game.
The one with more stones on the board at the end has won. For heaven's sake, what could be easier? This naturally leads to the question how stones come and go. Tell'm (skipping eyes), pair the suckers (sorry ;--), and start'm playing - on 9x9, to be sure.
Hold back yourself. Only tell'm what can be done, not what should be done. Relax. Enjoy watching their crazy games. Explain ko when it happens (and treat triple ko as tie - you won't believe what they come up with :--). Avoid any "super" solution.
At the end of round one - yes, we're doing a four-round Swiss Tournament - chart their results and explain'em what went completely wrong. Keeping open two eyes might be a good idea . . . Then start the next round. Don't worry, beginners don't really care about losing. After round two you might suggest the trick with the parking reservation - also known as "territory". Always pick up some situations from their games and explain'em.
After the tournament do a simultane with them - you should have your fun too. All they get is the start. Don't be gentle. Try to kill everything.
Gee, this was a great first day!
axd: ummm... I'm interested, what's this "trick with the parking reservation"?
Andrew Grant: I think what he means is that you can surround an area such that the opponent can't live inside, and so you can fill it up with your stones later on. Like reserving a parking space for your car; you don't have to park your car there straight away, but it prevents anyone else putting their car in the space.
axd: While I introduced the game to some young players in a park not far from where I live, I came across this situation:
The players started counting and I hesitated to bring 'a' into attention. For some players, the black group is alive; for some stronger players, that group is alive after occupying 'a'; for even stronger players, this black group is dead.
I decided not to intervene. But this brought me to following observations (of rather academic value) that teachers should be aware of:
Soon after I posted this, someone edited the diagram to remove the double atari threat, and demonstrated precisely what I try to point out to avoid as a teacher. Note that beginners might not be aware of double atari; it would not help them much to immediately point out such a situation!
Harleqin: I think that every game is only between the players until it is finished and the result agreed upon. Interruption by any outsiders is not proper. In the postmortem, you may show them anything you want, and should, if it is sufficiently simple.