You got a Duress/Thoughtseize as well as a Preordain/Ponder.
You are playing a combo deck, your opponent is the control in this matchup.

You want to play both cards this turn, do you:

• Play hand disruption first to inform your choice on what you are looking for with the cantrip,

or

• Play the cantrip first to inform you what to take with the hand disruption spell,

and why?

I personally tend to play hand disruption first in most cases.

I would play the Duress effect first for the reasons given; also because they may daze/misstep it and I would rather that happen and be able to recover with the cantrip.

Good question!

Loaded question because there are so many factors to consider.

• What kind of combo deck are they
• What match/turn is it
• What else in in your hand
• What does your on board presence / Mana look like

I'm not sure there is a right answer here, just contextual ones.

If you don't need the cantrip to resolve because your hand is fine then you can cantrip first but if you need the cantrip you want to duress first, if they misstep the cantrip the duress will resolve and excetera. Generally, I am interested in leading on the one need to resolve less.

I think 99% of the time you want to duress. Misstep is a 1-of, so more often than not, they are going to FoW it and give you a 2-1 if they have something in hand they want to save.

I assume you are on the play and this is your opener and you can't play both (with say a single underground sea as your only mana).

Maybe they have daze and an island to protect something next turn - and you want to stop the plan before daze gets online. This is vintage, and the plays your opponent can make can be devastating. Even if they are on control, there are plays worth stopping far greater than your resolved ponder.

The biggest worry would be them doing something degenerate like turn 1 tinker for citadel/BSC. Maybe they simply have ancestral, and pulling that is essentially a 3-for-1 in your favor if you duress it. Maybe they have great spells, but kept a greedy 1-land+lotus hand and you could mana cripple them immediately. Bottom line, if they kept their hand, it likely has at least one degenerate play or a line of "set up" spells like 1 land and their own ponder. Duressing that line could put you far ahead in the game.

And then there is always the fact that you gain the knowledge you need for how to set up your own cantrip and your best lines moving forward. It's almost never wrong to duress first. The ONE time I can see pondering first is if you are a mana source (ritual, lotus, vault, etc) away from going off and winning that turn. But even then, you have to hope you hit that mana source in the top 3 cards AND that your opponent doesn't have FoW, which a duress could stop anyway. That scenario seems like a trap, though - so I am saying duress first 99%...maybe 100% of the time.

Underground Sea taps are valuable. You can play a Duress with Dark Ritual mana. Preordain must be paid with Underground Sea mana. Something to consider.

@lienielsen
But do you really want to cast a Ritual, commit and then cast Duress? I don't like to go for it till I know the coast is clear, IE not cast Rituals till then.
I would cast the Duress before any Rituals; pay for it off of a Sea or a Swamp.

@lienielsen If you have the mana available to go off with a chain of rituals, then I might cast the first ritual, duress, then ritual #2 and go off. But in that instance, ponder/preordain isn't even necessary. I think the main question boiled down to "I have only an underground sea and have to pick the blue or black mode on my opener." My answer, whether "going off" or not, is always to go black first, for either duress or ritual/duress.

I wonder if the premise should be questioned. I think if you take it as a given that you're definitely playing Preordain and Duress this turn, most of the time leading with Duress makes sense. This is probably true for ordering Duress and any card. The key factor is that opening with Duress reduces your opponent's ability to make the right choice. If they have a response like a Mental Misstep or a Brainstorm, Duress forces them to use it when you choose, where Preordain gives them the option of using it when they think is best.

This is probably more important than the information advantage. To evaluate the information advantage, you'd ask:

• what kind of information might Duress reveal that would change how I resolve Preordain?
• what kind of information might Preordain reveal that would change how I resolve Duress?

After asking those questions you should see the trap in the original question. The most likely way for Preordain to change how you would play Duress isn't that you might have them discard a different card, it's that's drawing a particular card might make you not want to play Duress at all. If this is turn one or two and you haven't seen your opponents hand yet, Duress is high value and it's PROBABLY being cast right away. But in many mid-game or later situations, you want to be careful you don't Duress away some medium-quality draw spell and pass the turn, just to have them draw a counterspell later. You want to cast your Duress as close as possible to the turn you try to win (which is probably not this turn if you're worried about a Preordain getting Misstep'd). So I think another question to ask is:

• If I led with Preordain, what could I find that would make me not want to play Duress this turn at all?

If there's a pretty reasonable chance you'll find one of those cards, leading with Preordain is probably best. The other scenario I haven't heard mentioned in the thread is if you want your Preordain countered. If your hand isn't particularly reliant on Preordain then you may not care if it gets Misstep'd. An obvious example is if you have an Ancestral Recall as well, but it could just be the relatively common case of "your hand is totally fine, you're not missing anything critical, Preordain would just make it better". If you lead with Preordain and they Misstep it, then follow with Duress, you may be able to answer two key cards instead of one, which could be significantly better than whatever Preordain would have gotten you.

In some hands that line is particularly strong. If this is turn one and I'm talking about this line with a hand of Preordain, Duress, Underground Sea, Mox Sapphire - I'll hem and haw over my hand for a while, sigh and reluctantly keep, drop the artifact mana without playing the land, and sheepishly run out the cantrip. A lot of players will be extremely tempted to "get you" from this game state. If you can sink your turn one Preordain into their Force of Will and follow THAT with a Duress? The game is usually over.

Ultimately I think my heuristic is:

• Do I want my opponent to interact with the Preordain? (probably fairly common, easy to notice)
• Will the results of this Preordain make me choose not to Duress? (rare, but easy to notice if you're looking)
• If no to both, just Duress first

Those aren't the only factors to consider, but for me those are things that I can reasonably figure out in the middle of a tournament game