First hand is a keep IMO. 1-drop into 2-drop plus you have an out if you end up flooding (just sac Courier early).

Second hand is a mull, you're prone to flooding out with no aggressive pressure whatsoever.

That first one is a clear keep

You cast Doomfall on curve, opponent has Teferi and Approach, which do you pick? My board was Glint-Sleeve, he also had a seal away.

It would depend on what I'm playing and how many lands they have in play and in their hand.
But in most cases I'd probably take teferi because it's a more immediate threat, unless I'm playing something slow and Grindy.
My hand would be relevant too, if I have bigger threats than the siphoner in my hand I wouldn't mind it being sealed, but if I'm light on threats or if they're low on lands, I might risk taking the sealed away, especially since I would probably have a fair amount of vraska's contemps to draw to deal with teferi later.

I was playing RB Midrange, chandras and phoenixes in hand. In the end I took Teferi and lost to the approach 1 turn before I would kill him.

Opponent had 3 lands, was on the play.

Always take Teferi! The card is just too powerful, and serves as a win condition too. Approach isn't relevant until way later in the game anyway. If you lost to Approach one turn before you would kill him, that's like 10+ turns later so I doubt it's the fault of this decision. If he could answer all your threats, then taking Approach just means you lose slower.

However, if his hand is really short on removal, you could consider taking Seal Away and trying to draw multiple cards from the Glint-Sleeve Siphoner, but it's a rather unreliable plan since there's a high chance he'll just topdeck removal.

Yeah, he had settle at turn 5 anyway.

You're playing Dominaria limited. You're on the play, and in the first two turns both you and your opponent play lands and pass. It's turn 3. You have no 3-mana creature except Sergeant-at-Arms. You have a fourth land but your only 4-mana card is Dark Bargain. Do you play the Sergeant unkicked?

I suspect this is a difficult question to answer because of the many variables (what colors is opponent showing? are you holding removal? what else is in your deck? etc), but I'm wondering what goes through other peoples' minds when they make this decision. On the one hand, the 2/3 is likely to get stonewalled by the opponent's 3-drop, and might not even be able to block well. On the other hand, you're a long way away from kicking the Sergeant, and if you don't play something you risk falling way behind on tempo. What's the play?

Use your mana when you can, I see no point for not developing your board, you are not holding removal and you have T4 play if your opponent does not develop his board.
Also, 2/3 is a solid blocker.

I'd drop it. Sergeant is probably the one Kicker creature I often play unkicked because the kicker is somewhat low impact (solid blocker on turn 3 vs. three chumps on turn 6), and making sure you can strike a Dark Bargain in peace has value.

Different story on a turn 2 Skin-Witch/Chronicler obviously (I'll drop that only if it blocks an opposing 2-drop, else they are held for turn 6)

You're playing B/R against UW control and you've successfully resolved a Karn, Scion of Urza. You +1, opponent gives you a land exiling another Karn. On the next turn, do you -1 Karn to take the exiled Karn?

I lost two matches in this matchup just now and this was the major decision point I had. Both times I +'ed Karn, both times that just led to more lands, and both times after my opponent answered Karn I was very much hoping to draw Karn again. However if I take the Karn, I gain no immediate advantage and it's a dead card in my hand until my opponent draws an answer. Not sure, what would others do?

That is too dependant on the overall state of the game to give an easy answer.
In the dark I'd lean towards taking Karn though.

In the RB versus UW matchup Karn is best at building, securing and expanding on a long term advantage, but cannot close out a game quickly by himself.
Given that you resolved a Karn, not knowing the game state other than that I'd consider you to be slightly ahead and you probably want to capitalize on that even if your opponent deals with your Karn.



You're not gaining immediate advantage from +1ing Karn either since it's quite likely your opponent will give you a card that's not very effective against their gameplan anyway. Also, as long as your current Karn lives you are gaining long-term advantage; so unless you need to deal with an opposing threat or you have to finish them quickly they're heavily inclined to deal with Karn (since you're otherwise fighting and beating them on their own turf).

I always give them Karn over anything that would affect the board-but I no longer play UW so there is that-, in the situation you describe ... Karn is not doing much ... Teferi can single handle him if it comes to that, the best he can do is attract removal and clear the way for Chandra or the Rakdos PW... he is the real pain in the ass for control... Karn not so much IME

If Banedon runs the list I think he does, he's running 3 Chandra mainboard, 1 Angrath side. That's the extent of cards that are better than Karn against UW (especially since that deck would not run Hazoret).
And Karn is important because the longer one Karn sticks around the more chances he has to find these cards and return them not much later.

Against stuff that affects the board you have more than enough answers. Against too much stuff that affects the board you might be powerless - that's where Karn comes in.

Well both times I had no creatures in play or in hand, and was really hoping to get one so I can establish a clock. In the second game for example opponent was sitting pretty at 20 life, and the only reason I wasn't getting destroyed was because he had three Teferis which were being negated by Sorcerous Spyglass. Even a Pia Nalaar or Scrapheap Scrounger I'd have minused Karn to get. I dunno. Post-board against control I have fewer creatures, but in both games, Karn just kept drawing irrelevant cards (with both draws).

Well, from a control player perspective, the thought of an aggro player reducing threat density post board makes me erect.

-3 Rekindling Phoenix +3 Karn makes you happy?

About a push, but slightly, yes. You couldn't find other things like Abrade to cut to increase threat density? A 4 mana Walker who doesn't threaten any reach is pretty A okay. I certainly have just as many ways to deal.

Those are becoming Duress, Doomfall, Arguel's Blood Fast, Sorcerous Spyglass ...

Problem with Rekindling Phoenix is that against UW it's just a 4/3 creature with no relevant abilities. If it's answered by Seal Away, Essence Scatter, or whatever, I'm trading down mana by quite a bit. It doesn't even have Haste like Glorybringer. Since I have to cut something to bring in Karn discard etc, it still has to go.