Description based on the following primer source with some changes, credits to Shaper for taking time making the original Primer description: https://www.moxfield.com/decks/ilvW7g3hsUio09K2gLuDmg/primer

> Deck Description

Creature-Reliant Midrange, resilient to hate and removal; consistent; has great answers for artifact reliant decks. As a midrange deck, you’re not looking to be the fastest deck at the table - that’s reserved for decks like Thoracle Consultation, Food Chain, among other things. Rather, you try to slow down and answer the other decks as needed, build a board, and push for a win when the coast seems clear and you have the resources.

> Deck Stregths

Strong against countermagic and stax due to ability to use Yisan to develop board and find powerful mana sources.

You generally don’t need to worry about spheres, tangle wires, or orbs - that’s why you run them. Static Orb can be a pain, though you can easily destroy it if you need to or break parity on it with your untappers (quirion ranger, scryb ranger) + Exploration effects, with Seedborn Muse, or with Gaea’s Cradle. Playing out mana dorks and having big mana sources in Cradle, Priest of Titania, and Karametra’s Acolyte mean you don’t have to care about taxes.

Countermagic isn’t too big a problem for Yisan. Even though you can’t do anything about a counterspell - unless you have Autumn’s Veil / Veil of Summer or Allosaurus Sheperd / Destiny Spinner - you can usually sneak in Yisan early underneath countermagic. Defensive combo decks that play countermagic usually only want to defend their own combos or stop opposing combos if necessary. More control-focused blue decks might decide to counter an early Yisan, but oftentimes they have to save their countermagic for faster combo decks at the table.

> Deck Weaknesses

Yisan can be fairly reliant on other decks at the table to answer fast combo. Being monogreen, you often have little recourse to answering a turn 2-3 Ad Nauseum / Thoracle Consultation / etc. if you didn’t draw an early stax piece. Even later in the game, the stax pieces you play to try and ward off Ad Nauseum or similar wins can simply get destroyed or bounced and you lose to the player untapping and winning as a result. This is why it is important to start pushing for a win once you’ve built a board - if you give combo players enough time, they’ll be able to draw or tutor a win. Ultimately there will be games you lose to fast combo simply due to pod composition or other players not being able to answer the combo; this is just the nature of the format. Every deck has some games where it just isn’t winning.

Cursed Totem and Linvala shut down your mana and Yisan, forcing you to find an answer without using Yisan - however you have plenty of creature tutors to find an answer as well as the ability to draw a removal spell naturally.

Aven Mindcensor, Containment Priest, StrangleHold and Grafdigger’s Cage hurt you similarly, though they don’t stop your mana at least. They take away your ability to use other creature tutors, though.

If Aven Mindcensor, Linvala, or Containment Priest are particularly common in your meta, you may need to tech against them.

Tabernacle at Pendrell Vale is naturally a pain for a creature deck like this one. Thankfully, most decks don’t play this card, as the best stax decks currently tend to rely on mana dorks, save for Teferi. Even then, you can pay for a good deal of your board with a Priest of Titania, Gaea's Cradle, or Karametra’s Acolyte - you just have to slow down through Tabernacle.

Yisan struggles against Humility more than any other hate piece. ETB effect will not work against it so you have to rely on naturally drawing into an answer if you do not leave one up. It is important to note if any deck runs Humility in the meta you are playing in. Luckily, Humility is rather rare. The only decks that run Humility, off of the top of my head, are some Grand Arbiter Augustin IV builds and the Enduring Renewal brew.

Torpor Orb, although not as big a problem for the deck as other hate, is worth respecting as otherwise it can lead to misplays.

Can be hated out if enough creature removal and/or board wipes are thrown out to stop Yisan. If you’re afraid of a board wipe, you may have to play more conservatively and just rely on Yisan rather than playing any creatures from hand.

> Yisan or Selvala?

Selvala is a fast combo deck, focused solely on landing Selvala and comboing out from there. The deck is gunning hard to win on turn 3 or 4, though it can pull off wins on later turns after being disrupted.

Unlike Yisan, it does not try to play its own disruption, except for some removal to take out cards like Cursed Totem. Yisan also spends its time trying to slow down opponents through stax pieces like spheres and Winter Orb. Selvala doesn't really have any interest in interacting with opponents except when absolutely necessary.

Personally, I like Yisan better because it has a wider range of options and desition points, is slower but staxier.

> Gameplan

> Simplified

Put simply, your initial game plan is to get Yisan up and running in a timely fashion. Typically, you want to get him into play ASAP. From there, you want to work up the Yisan chain, pushing towards your win while disrupting when you need to or when you can afford to by playing removal or stax.

To facilitate the Yisan engine, you want to get an untapper and a mana engine. An untapper lets you start using Yisan two or more times in a turn cycle, while mana engines help you support these activations. The big mana producers also set you up to infinite combo with Temur Sabertooth / Ashaya, Soul of the Wild. Some examples follow below, but check the Verse Breakdowns for a more in-depth look:

Quirion Ranger, Scryb Ranger: These are untappers that return a forest to your hand. These are your go-to ones since it’s easier to support returning forests to your hand.

Wirewood Symbiote: This is an untapper that requires you to return an elf to your hand. You probably won’t be versing this out too early since it’s harder to support returning elves to your hand.

Seedborn Muse: Serves as both an untapper, due to untapping Yisan every turn, and a mana engine, as it untaps all your lands every turn. This allows you to use Yisan every turn, even more when combined with other untappers.

Priest of Titania / Circle of Dreams Druid: Generates a great amount of mana letting you fuel out both Yisan activations and spells from your hand as needed.

Karametra’s Acolyte: An even greater mana producer than Priest of Titania, but sits at verse 4.

Burgeoning combine well with Scryb Ranger or Quirion Ranger to make using their untap abilities every turn much less painful. You can, for example, respond to a burgeoning trigger by activating Quirion Ranger (or activating Yisan, fetching Quirion Ranger, then using the untap ability).

Quirion Ranger > Priest of Titania is a very common start. Assuming you open with a t1 dork, your Priest is creating at least 3 mana before factoring in other players elves, or any additional verses (Rec Sage on 3, etc.)

> Mulliganing

Generally speaking, you’re looking to find a way to drop Yisan on turn 1 or 2. The deck is decidedly commander-reliant; it doesn’t function without Yisan available, so getting him in play as early as possible is virtually never incorrect. The rare exceptions to not mulliganing to a t1 accelerant are fairly match-up specific: a turn 2 Sylvan Library in a very grindy game for example.

Depending on the table you may have to mulligan for a stax piece - t2 Yisan with nothing else to stop a fast t3 combo is an easy way to lose if you can’t rely on other players at the table to interact with the combo.

> Breaking down the song, verse by verse...

> Verse 1 - Targets semi-ordered by importance

Sylvan Safekeeper - Protection. Constantly active way of protecting your Yisan / other creatures from targeted removal. Players are rarely going to want to trade a card and the mana investment just for one of your lands, so having this in play is great deterrent on its own.

Quirion Ranger - An untapper for Yisan and your Priest of Titania, as well as an elf. Preferred early, especially with an Burgeoning effect. Having an untapper is great for helping you work up the Yisan chain more quickly, as well as being able to double verse (see Miscellaneous Advice for explanation on Double Versing).

Allosaurus Sheperd - Cancels all countermagic in the deck and let's you assemble a big spell like Finale of Devastation early on. Mulligan or Pod composition will determine if you look for it.

Wirewood Symbiote - Another untapper and part of Temur Sabertooth / Ahaya, Soul of the Wild combos. Also acts as protection for your elves, as you can return one to your hand in response to a board wipe or spot removal. Harder to turn online early, as returning a dork to your hand removes your access to the mana that the dork would produce, as well as having to re-cast the dork.

Arbor Elf - Gets a special mention among the mana dorks due to its ability to generate 2 mana from forests enchanted with Wild Growth / Utopia Sprawl.

Other mana dorks - Usually the other targets are better but occasionally you just want more mana or need to up your elf count later in the game when you’ve lost the better 1 drop targets. However you can always double-verse and skip verse 1 to get two 2 drops in later points of the game.

> Verse 2 - Targets semi-ordered by importance

Priest of Titania - Huge mana engine, especially when combined with untappers. Part of Temur Sabertooth / Ashaya, Soul of the Wild combos. Notably, this card counts all elves in play, which is hugely relevant since many decks will play some number of elves.

Scryb Ranger - Fills the same function as Quirion Ranger, but is not an elf. If you search first for Sylvan Safekeeper you have this unttaper option later on...

Phyrexian Revoker - Answers problematic permanents such as Food Chain, Lion’s Eye Diamond, or just mana rocks like Mana Crypt. Additional targets include Isochron Scepter, Aetherflux Reservoir, Hermit Druid, Nomads En-Kor, Selvala, Sisay, Najeela, etc.

Destiny Spinner - Same effect as Allosaurus Sheperd but only for creatures and enchatments.

Collector Ouphe - Shuts down all activated abilities on artifacts.

Scavenging Ooze - Instant speed targeted grave hate. The potentially big power/toughness can be relevant too.

> Verse 3 - Unordered

Circle of Dreams Druid - One of the best mana dorks in the format, specially on this decks that brings a ton of creatures to the battlefield. Combo piece for Temur Sabertooth and Ashaya, Soul of the Wild.

Manglehorn - Artifact removal and great at slowing down artifacts. Mana rocks come into play tapped which makes Grim Monolith, Mana Vault much worse and doesn’t allow your opponents to generate mana from drawn fast mana rocks. Also puts things like Isochron Scepter into play tapped. Asymmetric unlike Root Maze, so your own artifacts are unaffected.

Reclamation Sage - More versatile removal than Manglehorn and is an elf.

Selvala, Heart of the Wilds - Strong for infinite mana combos.

Endurance - Great response for Thoracle Consultation combo's as well as any graveyard combo that an opponent can have.

Eternal Witness - Can recur a lost important card. With infinite mana and Temur Sabertooth on the battlefield can recur a Beast Within and destroy all the battlefield (including lands).

> Verse 4 - Unordered

Karametra’s Acolyte - Generates an incredible amount of mana. Useful in Temur Sabertooth / Ashaya, Soul of the Wild combos, or just for the resources.

Temur Sabertooth - Useful in combos, but has many other uses as well. Can return creatures to your hand in response to board wipes or removal. Can return untappers to your hand on your turn to reuse them, circumventing the once-per-turn activation restriction.

Thought-Knot Seer - A great way to interact with combo decks. TKS can be put into play instant-speed off of Yisan. This lets you take actions such as tutoring TKS in an opponent’s draw step after they draw a card they tutored with vampiric tutor. Notably, if the card they tutor is an instant such as ad nauseam, they can just cast it in response if they have the mana. However, this lets you hit tutored combo pieces or other important cards. You can also use TKS if you think an opponent is sandbagging an important spell or a board wipe. In a Temur Sabertooth / Ashaya, Soul of the Wild combo, TKS can be bounced infinitely with infinite mana - this lets you draw your opponent’s decks out - but be careful, as they may draw into an interactive spell. Generally, you might loop Beast Within and Eternal Witness first, let mana pools empty by moving to second main, then looping Thought-knot Seer. Notably, you need infinite green mana and infinite colorless mana, which can be tricky to achieve. If you have a Boreal Druid tapping for mana in your combo turn, then you can just use that. You can additionally do something like looping a removal spell on your own sol ring, returning the sol ring to your hand, and recasting it to effectively untap it and turn infinite green into infinite colorless as well.

> Verse 5 - Targets semi-ordered by importance

Ashaya, Soul of the Wild - The most important 5 drop, beacause if you are here, you already have the combo assembled, its ability doesn't require an activation so as soon as it hits the battlefield you can have infinite mana, infinite untap steps, infinite bounces, etc.

Seedborn Muse - One of most important 5 drop in any Yisan deck, this makes it easy to activate Yisan on each opponent’s turn while even having mana for other actions. However, be aware that by the time you’re on verse 5, you only need to activate Yisan a few more times to get to verse 8 for Craterhoof Behemoth. Seedborn is especially powerful if fetched out with a non-Yisan tutor, when your Yisan is at lower verse counts. You may even want to skip Seedborn and get a double 6, because using muse to get through the later verses can be very unnecessary - you may instead want to have access to it if you get your board wiped and need to rebuild. Also with Ashaya it's no longer necessary because usually you'll have infinite untap activations, so think of it as the best card for tutoring or casting in turn 2-3.

Somberwald Stag - A necessary tutorable answer to cards such as Linvala. However, you won’t be able to Yisan out Stag to kill a Linvala. More likely, you’re just tutoring and casting the Stag. You can Yisan for Somberwald Stag if there’s another problematic creature in play that needs to be answered, such as an opposing combo piece, or a threatening Zur.

> Verse 6 - Unordered

Woodland Bellower - Can find a missing part of Temur Sabertooth / Ashaya, Soul of the Wild combo, or just get an interactive creature. Remember that you can’t tutor Revoker off of it.

Great Oak Gurdian - Great for combo with Temur Sabertooth / Ashaya, Soul of the Wild, bounce it infinite times with a big mana dork in the battlefield and you will make your creatures have infinite power, usually you'll have enough creatures to kill you opponents without trample.

Kogla, the Titan Ape - Great card to deal with Linvala or other pesky creatures as well as artifacts later on.

> Verse 7

Regal Force - We don’t have many options for good 7 drops but Regal Force can be great at breaking a stall, especially with a Cursed Totem in play, and giving you a bunch of cards to play with. If you can infinite bounce it you can draw your deck and use other infinite combos.

> Verse 8

Craterhoof Behemoth - The easiest and most important win condition of the deck. To calculate damage, first count the number of creatures you have in play when Craterhoof enters. Multiply that by the number of creatures you have that can attack (untapped, not summoning sick). This is the amount of pump damage. Then add the normal power of your attackers. Remember that all your creatures gain trample, so it is usually simple enough to subtract the toughness of opposing blockers. Craterhoof isn’t always enough to kill a whole table. Usually, however, people are losing life in combat and from their own card draw effects, so you may only need to deal 80 damage to kill 3 opposing players. This is why getting in safe attacks, even early on with your Phyrexian Revoker, can really add up over time. Also if you can infinite bounce or you combo with Great Oak Guardian and then go to Verse 8 for Craterhook you instantly win on damage.

> Winning

> Craterhoof Behemoth

See Verse 8. This is your primary win that you work towards, and it sits right at the end of the Yisan chain. Of course it’s certainly possible to hardcast Craterhoof. Just make sure to calculate the math, and be wary of running into countermagic. Sometimes it’s sufficient to not kill the entire table, but just the players who are the biggest threats to you.

> Temur Sabertooth Combos

Temur Sabertooth + creature tapping for 5 or more mana + Wirewood Symbiote + Elf (1 cmc hopefully)

Typically the creature is Karametra’s Acolyte or Priest of Titania. Tap the Priest for 5 mana, return the elf to your hand with Wirewood to untap her, return Wirewood to your hand with Sabertooth (-2 mana), replay wirewood and the elf (-2 mana, -4 mana total). This generates infinite mana and allows you to abuse Sabertooth and an ETB, often Eternal Witness

A direct line to get you to Temur Sabertooth combo is something like:

T1 Dork > T2 Yisan > T3 Verse1 for Quirion Ranger > T4 Verse 2 for Priest of Titania > T5 double 4 for Karametra’s Acolyte and Temur Sabertooth >T6 untap and go through verse 5 getting anything, get Woodland Bellower on Verse 6 to find wirewood symbiote, and combo off there. At this point you generate infinite mana, infinite untaps, and can use infinite ETBs. You can bounce and replay Woodland Bellower to get any green creatures with cmc 3 or less out of your deck, including Eternal Witness. You can Yisan on 7 to to get Regal Force and draw your deck by bouncing and replaying that. You can Yisan on 8 for Craterhoof and create infinite power/toughness by bouncing and replaying that.

As you play the deck and goldfish it you’ll learn to adapt these sort of lines to fit the board state and your hand. With enough elves in play, from yourself and other players, you might not need Karametra’s acolyte at all. With creature tutors in hand, or from drawing naturally, you may be able to go faster by having more untappers or use verses on utility cards instead.

> Temur Sabertooth + Great Oak Guardian + creatures tapping for a combined 8+ mana.

At 8 mana you get to make your creatures infinitely big and have to win with combat. If your creatures tap for 9 or more then you generate infinite mana. If you generate infinite mana you can, for example, then use Yisan as much as you can (likely only 7 and 8 drop if you Yisan’ed into GoG). Additionally with infinite mana you can loop Temur Sabertooth and another ETB effect, such as Eternal Witness, and attempt a win that way. To reach creatures that tap for enough mana you’re likely going to need Priest of Titania and/or Karametra’s acolyte. To get Karametra’s Acolyte while also having Temur Sabertooth, you can use an untapper to double activate Yisan to get two 4 drops instead of a 3 and a 4 drop.

> Temur Sabertooth + Great Oak Guardian + Selvala, Heart of the Wilds

Similarly generates infinite mana and infinite P/T but doesn’t necessarily need creatures tapping for 8+ to start. Since Great Oak Guardian grows your creatures, Selvala will likely be tapping for more and more mana. With a bit of starting mana this line can be fairly compact. It also lets you neatly Yisan for 3 to get Selvala, then for 4 to get Temur Sabertooth. Note that this combo does not draw your deck using %Selvala; even though you can bounce creatures to reset their power/toughness, since your Sabertooth is getting infinitely big, it will keep you from drawing cards off of Selvala unless you can kill or bounce your Sabertooth (beast within, song of the dryads, duplicant). However since you likely have Yisan in play and infinite mana / untaps, you can then Yisan for Regal force to draw your deck or Craterhoof for infinite trampling damage.

> Umbral Mantle

With a creature tapping for 4+ mana, this nets infinite mana. You can use this mana to make creatures that can tap themselves infinitely big (Power/Toughness) using umbral mantle, provided they aren’t summoning sick. Eg. Generate infinite mana with Mantle+Priest of Titania, then make your Elvish Mystic, Birds of Paradise, Sakura Tribe Scout, etc. infinitely big and win through combat. Additionally, with infinite mana, Umbral Mantle can be used cleanly with Yisan. You can even use the Umbral Mantle untap in response to Yisan activations to get multiple creatures of a single verse.

One fringe win, if you have Umbral Mantle + Staff of Domination in play: If you can’t win simply by drawing your deck (eg there is a notion thief-style effect in play) then once you’ve made infinite mana, you can use Staff of Domination to tap down your own creature then untap them with Umbral Mantle to make any one of your creatures infinite power/toughness. Staff of Domination can tap down blockers as well.
Umbral Mantle is also specifically good at going off with Selvala.

> Staff of Domination + Creature tapping for 5+ mana

Makes infinite mana, draws infinite cards, gains infinite life. Makes for compact wins, but like umbral mantle, is disabled by your own Null Rod and can’t be tutored for. Once you’ve drawn your deck you can loop Temur Sabertooth and Eternal Witness (+ Beast Within), Thought-Knot Seer + Temur Sabertooth draw your opponents’ decks out.

> Miscellaneous Advice

> Double Versing

If you activate Yisan, hold priority, untap Yisan and activate again, you get two tutors for creatures of the latest verse. For example, your Yisan is at 2 counters. You activate Yisan, hold priority, untap Yisan with a Quirion Ranger, then activate Yisan again. Yisan is now at 4 verse counters (since they are put on as an activation cost) and you can search for two 4-cmc creatures. This is important because sometimes you want multiple creatures at the same CMC, such as Karametra’s Acolyte + Temur Sabertooth at 4 cmc, or don’t really need anything from a certain CMC and can afford to “skip” it for a higher cmc option. With enough mana, and multiple untappers, you can triple verse, but this is often not particularly relevant.

> More...

Rarely need to tap out on your own turn, one of Yisan’s greatest strengths is the ability to play from the deck and play at the end of someone’s turn. It was stated in the section to play against wraths, but to be honest discouraging against just dumping your hand in general really is worth mentioning more than once. Its one of the most obvious signs of a bad Yisan player. Double versing is an important tool that should be remembered, it can help created accelerated lines of play.

Don’t play too “slow” - Even if people are stuck under stax and you have a Sylvan Safekeeper and a lot of mana, you need to push for the win. Giving your opponents too much time opens you up to losing to an overloaded Cyclonic Rift, a Toxic Deluge or other wipe, or someone finding their way around your stax.

Burgeoning is a Triggered Ability - You can activate Quirion Ranger in response to a burgeoning trigger, then put the land you bounced into play

Versing in response to Tangle Wire trigger

Staxing is typically your strongest play in most early board states. Yisan is not a fast deck by conventional cEDH metrics; you will rarely win flat races.

If you can comfortably skip Seedborn on 5 (or you see something like tutor for a held deluge), it’s probably fine to do so. If you lose Yisan or get wrathed, she’s the strongest single card to rebuild your board.