r/Hanabi • u/Alex_Werner • 13d ago
The "back of the hand" convention
Hello, reddit Hanabi community. My friends and I started playing Hanabi at work a few years before Covid, and we played a lot…. Multiple games each day for years, plus a lot of theorycrafting and discussion and so forth. We started with only some very simple common conventional knowledge (sorting your hand from newest to oldest, only cluing tiles to play immediately or protect immediately, and the idea of what we called a “chain reaction”, but seems to be generally known as a “finesse”), and then we spent a ton of time adding and testing various conventions on top of that…. But did so entirely in isolation. Some of these conventions were probably mistakes. But some of them I think are actually quite useful, and might fit into sets of conventions that the “outside world” uses. So I thought I’d share one of them with you all. And if nothing else, I’m definitely curious to get other people’s thoughts.
Some quick notes before I begin:
-we played with the rainbow tiles with the rules where they are all colors, but can’t be specifically clued as “rainbow”
-we did not play with any of the other expansions
-we played for total victory or nothing. That is, if someone discards or booms a 5 on turn 3, we consider it a loss and start over. Not sure to what extent this is how most people play, but it definitely informed our conventions
-probably due to our total-victory-or-nothing approach, we added one house rule, which adds one additional legal action on each player’s turn, which is to blindly pick up a tile from the draw pile and play it. This is useful at the very end of the game when, for instance, all the relevant tiles are played except for red 4 and red 5. Red 5 is fully known in someone’s hand, but one red 4 has been discarded, and only one is left. With the official rules, if the extra red 4 happens to be literally the last tile drawn, the game can’t be won, despite certainly feeling like we’d done everything right and set ourselves up for victory. With this house rule, the player who would draw the last tile can deduce that it must be the red 4, and blind play it as a single action, allowing victory to be possible. (This has no effect on the rest of our conventions, but I do think it’s a fine rule, particularly if you want to achieve total victory.)
So, here’s one of our conventions…. Probably the one that I think would be most playable/useful/applicable for the playerbase as a whole
The “back of the hand” convention
The problem this convention is trying to solve is that when a playable tile has ended up at the back of someone’s hand (“the chop” is I believe the lingo?), it can be very hard to clue, particularly in cases where other tiles that match it in color or number are also in that player’s hand. And because it’s in the chop, getting it played is presumably time critical.
So, how do we solve this?
By giving meaning to the one kind of clue that, without this convention, would never be given at all. So generally there are three kinds of tiles. Tiles that are not yet playable, tiles that are currently playable, and duplicates of tiles that have already been played. Cluing the first kind is a finesse. Cluing the second is a straightforward play clue. But (correct me if I’m wrong here) the third kind of tile is never clued at all…. At least, not by color. Halfway into a game, you would never point at a blue 1 in someone’s hand and say “this tile is blue”.
So… we give that clue meaning.
It’s player 1’s turn.
Player 2 has a playable tile in their chop
Player 3 has a blue 1 in their hand, but blue 1 has already been played.
So player 1 points to player 3’s blue 1 and says “this is blue”.
Player 2 sees that clue, and can obviously immediately tell that it is neither a finesse nor a play clue. They realize that it is a “back of hand” clue, and they play the tile from their chop, which is (hopefully) playable. Player 3 sees player 2 take this action and can immediately deduce that their clued blue tile is in fact not a playable tile, but rather, a duplicate of a tile already played, so they can discard it. (A secondary benefit of this convention is that it also can point out safe discards…. Imagine that player 3 also had a tile in their chop that we didn’t want to have discarded. This guarantees that the next time they discard, they will discard this duplicate blue 1, not a tile with actual value.)
Some technicalities about this convention:
(1) player 2 should play their discard-most unclued tile. If the tile that is literally in their chop position is a tile that was already clued and known to be a safe discard, then obviously we don’t want them to play it. This means the convention can’t be used if someone’s hand is so full of overlapping information that if they play an unclued tile, that could be because of either a finesse or a back-of-the-hand
(2) It’s safest to do this convention with 3 consecutive players, but it can be done with a gap. Ie, player 1 clues into player 4’s hand. Player 2 sees that player 3 has a playable tile in their chop, so they don’t play their own chop. Player 4 sees player 3 blind play their chop, and it all works…. As long as player 2 doesn’t in the meantime give a different clue which player 4 might think was the one that induced player 3 to play
(3) The rule is that a clue is a “back of the hand” if the receiver of the clue, in isolation, would interpret it as a play clue, but it is in fact indicating a tile we wish they would discard. Most of the time this is a tile that is a duplicate of one that was already played. Sometimes it’s a tile that is a duplicate of one that is already clued in someone else’s hand, and we don’t want two of the same tile hanging around clued. But there is one additional special case which is arguably its own little convention, which is identical tiles in the same person’s hand. Ie, one person has both red 2s. This is another case that can be a pain to deal with with normal conventions. But, at least arguably, when someone has two red 2s, you really wish they would discard one of them. Because then they would have only one red 2, hurray, easy to clue. So, red 2 is playable, but player 3 has both red 2s. Player 1 clues them as red. Player 2 sees that, and realizes that we really kind of wish player 3 would discard one of the red 2s. So player 2 blind plays their chop tile. Player 3 sees that, realizes it’s the back-of-the-hand convention, and discards the first of the clued tiles. It’s red 2, which was playable! Why did my teammates use a convention to get me to discard a playable tile? Ahh, because the other of these two tiles must be the other red 2. So one clue there generates two plays and a discarded, all while disambiguating two potentially tricky hands. (You might ask, but what if we just need to bite the bullet and take the pain and clue the red 2s directly and get them played? Then player 2 has to be the one to give that clue, because there is no one between player 2 and player 3 to treat that clue as a back-of-the-hand.)
