Who here interprets multi clues like this?

[Bananyan]

Suppose you have a card marked green.
x x G x x

You are then given a yellow clue, which changed the green into a multi
x x M Y x

Do you play the yellow, or do you play the multi? I've had a master level player with maybe 4k games tell me "everybody plays the multi because it is on the left".

[Lara8818]

I'd say the yellow, reason being if you want to indicate the multi card, there are usually easier ways to do it that don't splash over onto other, unplayable cards.

Especially in the example you give, where the yellow is to the right of the already-green-marked card and thus definitively is not multi itself.

It can get tricky when someone's already got one multi marked at a single color, and it eventually becomes playable, but since then they've drawn other multis. In that situation I wouldn't mark more colors at all, just number-mark or wait for an opportunity to finesse.

[Daredek]

I would play the M = play left convention.

It has to be a very unusual situation to be worth it to get that MC played.
Number blocking; no other color available as a second clue.
Going to cost two clues.
Is the yellow also playable or a save.

But lacking 'best card clued', I play left.

[Signy33]

I'd play yellow, and i don't think i've encountered many players who'd play the multi.

[Wreckage]

If yellow is clued, you should play the leftmost yellow card, not the multi. The multi is splash.

[Romain672]

Yellow 'obviously'.

This:

I'd say the yellow, reason being if you want to indicate the multi card, there are usually easier ways to do it that don't splash over onto other, unplayable cards.

The main goal of the other pov is to save a potential y2.

But why do you want to use some of the most common hints to play that marked card that you can get anyway now or later with a finesse?

[MoiMagnus]

Assuming I play with my friends, the "M" without hesitations, because that's the leftmost card you just clued, and that's how we play.

Assuming I play with strangers, I don't know. Depending on how urgent it is to play, I might consider the clue to be ambiguous (precisely because there is this other way to read it) and find another thing to play/clue. But then, I almost never play with strangers, so I don't know.

[Wreckage]

Yellow 'obviously'.

I agree.
If yellow doesn't mean yellow then there is no way to clue a playable card that's right of the multi. You will have to always wait until it hits chop, then save it. Then wait for another playable card on the left you can clue with color. Then hopefully find a chance to clue the yellow later.

This is so much more work than yellow=yellow. Clueing the multi is easy here, why should clueing the yellow be impossible?
If you are currently playing with the convention that this means the multi, I encourage you to change that convention so that you are free to clue either card.

[Daredek]

Any chance of posting the table number?

[Travis Hall]

I play the yellow, and MoiMagus [editted: not Wreckage, I misread the earlier attributions] has hit upon the reason why without realising it.

See, where possible we should give unambiguous clues, so that our partners know what they should do. We never want to leave them guessing which card to play. At the first level of deduction, this clue touches two cards in different ways, so it is not clear which card is the focus of the clue.

So, noting that touching both cards is ambiguous, to clue the multi (as clue-giver), I should choose the colour that will only touch the multi. (There will always be one, unless another multi is involved; and if there’s another multi there’s no choice but to target both.)

Now, if I’m cluing unambiguously when possible, when would I use the ambiguous yellow clue? Only when I have no other choice! So in this situation, since I chose yellow, it must be because I wanted to target yellow.

And when I’m receiving the clue, I run through that logic and reach the same conclusion.

We should maintain discipline and minimise splash in order to retain the best cluing options and allow our partners the ability to confidently respond. This applies to multi cluing and a lot of other situations.

(What do we lose by taking this approach? Only the ability to perform an incidental save when a playable multi is held and marked. We don’t lose the ability to save; we just have to spend another token to do it. This is a small price to pay for the benefit of being able to give clear clues in many more situations.)

Incidentally, this also leads to a variety of cluing techniques to fit particular circumstances. Suppose no cards are marked in a hand, 1g, 1y, and 1m have been played (so we are looking for 2s in each of those suits, but not others), with three players: Alice, Bob, Charlie.

If Charlie holds 2w x 2m 2y x (assuming the x cards are nothing that interferes) Alice or Bob can clue 2m with a colour, wait for the play, then clue yellow for 2y.

If Charlie holds 2w x 2y 2m x, Alice or Bob can clue yellow for the 2y, then another non-white colour for 2m. They can even do that in consecutive turns, so that Charlie doesn’t have time in between to play; but they don’t have to.

But if Charlie holds 2w x 3m 2y 2g, they can’t safely give any play clue. What then? Well, in that case Alice clues green, and Bob clues yellow, or vice versa. The second clue serves as a form of correction for the first, telling Charlie that both clues have targetted a coloured card to the right of the multi, and thus the multi is not the playable card for either clue.