Here’s a quick overview of the conventions that my friends and I use. There are two primary ideas on which they are build (note, by the way, that we always play for total victory… so if we discard a 5 early in the game, we just lose and start over, as opposed to playing to get as many tiles out of 25 as possible):
(1) Everyone’s hand has an order, newest to oldest. (When you start, your tiles/cards are in a random order, of course, but you just pretend they are sorted newest to oldest). Everyone keeps their hand in this order, and when you discard a tile, you always discard the oldest tile that you have not been given clues about. The benefit of this is that everyone knows what tile the other players might possibly discard. So, for instance, if you have a 5 in your hand, which is a crucial tile, but it’s not currently your oldest tile, then I am 100% confident you are not going to discard it, so I don’t yet need to spend time cluing you about it. When you draw a new tile, you add it to the other side of your hand, the newest side, which is referred to as the “play side”, for reasons I will explain below.
(2) Generally speaking, clues mean “play all these tiles right now”. So what you do not do with these conventions is tell someone “hey, these three tiles are all fours”, just because that’s useful information to have, and they can remember it and gather it up along with other information and eventually make useful plays down the road. So when you indicate multiple tiles in someone’s hand, and say “these are all red” or “these are all twos”, you are instructing that player to play them all, newest to oldest, one by one. Now, the obvious objection to this is, what if the tiles are in the wrong order in the person’s hand? Or what if there are gaps, like they have 124 of reds, but the rules require that you clue all the reds? And the answer is that once the player has played at least one tile out of their “play queue”, any other clue given to that player means “also, stop playing from your current play queue”. So, if everything was working out smoothly, and Bob had 124 of Reds, Alice would say “these are reds”, pointing at all three of them. He would play the 1. Then on his next turn he would play the 2. Then before his next turn Alice would point to some other tile in his hand and say “this is green”, and he would then play that green tile, and remember that he had a red tile, but know that it was not the red 3. You can also address tiles being in the wrong order by two players both giving clues. So if Charlie’s hand contains 321 of reds, but in the backwards order, then Alice can point to them and say “these are all reds”, and then Bob points to the middle one and says “this is a 2”. Charlie then realizes that the tile closest to his play side can’t be a 1, because if it was, Bob wouldn’t have given the second clue. He knows the middle is a 2, and now he deduces that the third one must be the 1, so he plays all 3, and you got 3 plays out of 2 clues.
Putting those two principles together, you get to what is the most fun and awesome component of these conventions, which is chain reaction clues (chain reactions generally only apply in 3- or more player games).
So suppose I look at the next two player’s hands, and they are (newest to oldest) (no tiles yet played):
Player #2 R1 G3 W4 W5 W4
Player #3 G4 G2 R2 B3 B3
So the Red 1 and 2 are both there ready to be played. But it will take two clues to get them both played, won’t it? As it turns out, it will not. What I do is point to the red 2 in the third player’s hand and say “this is red”. The second player sees me do that. Well, that seems like an insane play. I’m telling the third player to play their red 2 when there are no red tiles played yet. Madness! What could explain that? What I’m doing is giving a chain reaction clue. So player #2 pulls the tile off of his play side and plays it, without ever having been given a clue at all. And, presto, it’s the red 1. A chain reaction!
Now, that might seem very unlikely to ever come up. But remember, as we draw new tiles, we always add them on the play side. So imagine a situation partway through the game, where we’re all waiting for a Green 2 to be drawn. When the green 2 is drawn, it will always be added to someone play side. At that point, as long as anyone as a Green 3 anywhere in their hand, a chain reaction will be available.
Some more examples of chain reactions:
(1) The same situation as before, but the order of the players is reversed
Player #2 G4 G2 R2 B3 B3
Player #3 R1 G3 W4 W5 W4
I can still give precisely the same clue, and if player #2 is alert, the chain reaction can still work. This is a reverse chain reaction. It’s more dangerous, because what makes the normal chain reaction work is that player 3 doesn’t even get a chance to (incorrectly) play their R2 before player 1 has played the R1. But the key is that everyone should always be keeping an eye on the play side of everyone else’s hand. If you are clued a red tile in the middle of your hand, and someone else has the R1 literally on their play side, then you probably should NOT play, because it’s almost certainly a reverse chain reaction.
(2) Player #2 R1 R2 W4 W5 W4
Player #3 G4 G2 R3 B3 B3
A multi-tile chain reaction. I tell player #3 their middle tile is red. Player #2 sees that, sees that it seems insane, and deduces that his first and second play tiles must be R1 and R2 in that order. Player 3 sees player 2 play his R1 despite not being clued, realizes a chain reaction is afoot, sees that player 2 also has R2 coming, so deduces he must have R3. Three plays with one clue!
(3) Player #2 R1 R2 W4 W5 W4
Player #3 G4 G2 R3 R4 B3
Same as previous example, but my clue to player 3 is both is red tiles, which become a play queue, but which he doesn’t even begin to play until R1 and R2 have both been played
Player #2 R1 B3 W4 W5
Player #3 R2 Y2 Y2 Y4
Player #4 G4 G2 R3 G5
A double chain reaction! I clue player #4 his red 3, and player #2 and player #3 both blind play off their play sides.
(5) Here’s where it starts to get REALLY awesome
Player #2 G1 G2 R1 B5 Y1
Player #3 Y3 Y3 R2 B4 B4
I clue player #3 his red 2, “this is red”. Player #3 sees me give that clue, and thinks to himself “ahh, yes, it’s a chain reaction, I must have the R1 here on my play side”. So he pulls the tile off his play side and plops it down. And it is NOT R1… Oh no! But, wait, it’s G1, and G1 can ALSO be played. Then it gets to player #3s turn. Remember, he was clued a tile, which normally means he’s expected to play it. But, hold up, he just saw player #2 do something really weird, just pull a tile off his play side and play it despite being given no clues whatsoever. So he realizes that the red tile he was clued must NOT be the R1, because if it was R1, there would have been no chain reaction. So he just hangs onto his red tile. Then the next time we get back to player #2, he’s thinking “well, I must have the R1 in here somewhere”, so he plays the next tile on his play side (not the newly drawn one, of course), and it’s the G2. Then on his NEXT turn he plays the R1, and then Player #3 plays the R2. Presto! Four plays with one clue!
This is called a “lying chain reaction”, and it is SO MUCH FUN.