Hello everyone and welcome to my guide! I'm your host, kurooaisu, as you may or may not now, a League of Legends player who doesn't really play League so I'm basically nobody. I also like trying troll builds, theorycrafting, and writing, so since I discover this awful shenanigan called Mathematically Correct Master Yi, I'll just write it anyway.

"No experience? What are your qualifications to make build, then?"

To be honest, just maths. That's all.


Master Yi is a champion in League of Legends. He has tempered his body and sharpened his mind, so that thought and action have become almost as one. Though he chooses to enter into violence only as a last resort, the grace and speed of his blade ensures resolution is always swift. As one of the last living practitioners of the Ionia Crest icon.png Ionian art of Wuju, Yi has devoted his life to continuing the legacy of his people—scrutinizing potential new disciples with the Seven Lenses of Insight to identify the most worthy among them.

However, in game, Master Yi tempered his blade, body, and concentration by meditating in public as a form of BMing. He has also sharpened his skill to press REQQQQQ, right click, and stomp enemies with his 'mechanical outplays' while making his enemies salty about his untargetability. That's what True Masters do (probably).

And that's exactly the goal of our Mathematically Correct Master Yi build, which is to press Q as many times as we want in quick succession. By maximizing our Q to increase Master Yi's (debatable) outplay potential.



On the further parts of this guide, I'll just call this build guide MCMYi to make it simpler

Goal Of This Build

A general overview of our build plan. This part will explain what to achieve in this build and the factors that help you to achieve it.

The Q Factors

In this sections, we will talk about the outside factors that can help you accelerate your Q cooldown.

Mathematical Calculation

Want to see how MCMYi work in a 'mathematical' point of view? This part will explain the methods to shorten Master Yi's Q cooldown through mathematical formula.

Runes and Items

Jumping straight into the action (the actual build). This section will explain the runes and items we need to achieve MCMYi.

Tips and Combos

Some tips and combos for Master Yi and MCMYi, from the usual to unusual ones. Mathematically obliterate your enemies!

Closing Words

Final words from the author.

As stated earlier, the goal of this build is to maximize cooldown reduction of Master Yi's Q, Alpha Strike.

Alpha Strike COOLDOWN: 18 / 17.5 / 17 / 16.5 / 16 ACTIVE: Master Yi vanishes and becomes unable to act and, after 0.231 seconds, marks the target enemy and then moves to mark the nearest visible un-marked enemy within 600 units, recurring up to 3 times, once every 0.231 seconds. Upon finishing marking, or if there are no longer any targetable enemies, he reappears and becomes able to act again 「 after 0.165 seconds 」in front of the target and deals physical damage to all marked enemies, increased against monsters. If the target dies or gets too far away during the delay, he will reappear at the cast location instead. Basic attacks on-hit reduce Alpha Strike's cooldown by 1 second.

1. While you are casting Q, the cooldown of this skill doesn’t freeze, it counts down. This means that if you get the full duration of Q, your cooldown is further reduced by (0.231 x 4 targets) (duration of marking enemies) + 0.165 (duration of reappearing) = 1.089 seconds.
2. With 16 seconds cooldown, every small amount of Ability Haste matters. For example, with only 8 Ability Haste, the cooldown becomes 14.8148 seconds! You saved almost 1.2 seconds!

16 seconds cooldown at max level seems very long, right? But hear me out: with the right combination of items and runes...




And this is the main purpose of our build! Turning your combo to Q + AA + AA + AA + Q + AA + AA + AA + Q and so on.


The first way is by utilizing your passive, Double Strike.

Double Strike After landing 3 basic attacks, Master Yi's next attack within 4 seconds strikes twice, dealing 50% AD bonus physical damage which applies on-hit effects and can critically strike. If Double Strike’s first hit kills a unit, the second strike now searches for a new target within 300 range (prioritizes killing blows).

1. Double Strike is a weird passive. When you attack twice using Double Strike, your second strike will add one stack to its passive, so toward your next passive activation, you start with 1 stack instead of 0.
2. Double Strike applies both on-hit effects and on-attack effects (like Navori Quickblades and Kraken Slayer) on full effectiveness.


Of course Double Strike is not enough to achieve '3 attack Q Cooldown'. To further accelerate the cooldown of this build, we have to consider several factors: Ability Haste (as stated before), attack speed, and several more factors! I call them "The Q Factors".




Q Factors are every factors outside Master Yi's passive, Double Attack, that can accelerate the cooldown of your Q. Here are those:


Ability Haste is a statistic introduced to League of Legends in Season 11. This stat represents cooldown reduction, particularly cooldown of champion abilities. Ability Haste can be granted by items, buffs, and runes. It stacks additively with other Ability Haste sources.

How can Ability Haste influence cooldown? Here’s the formula:


Attack speed is a stat that is the frequency of a unit's basic attacks. They are measured and displayed as attacks per second. For example, if Master Yi has 1.5 Attack Speed, it means that Master Yi attacks 1.5 times in 1 second, 3 times in 2 seconds, 4.5 times in 3 seconds, and so on. Usually, Attack Speed is capped at 2.5 (or 2.5 attacks per second), but with the help of Hail of Blades and Lethal Tempo, you can exceed the cap temporarily.

The formula of attack speed is:

Guinsoo's Rageblade is one of the core items on On-Hit Master Yi, and it can also be used to create MCMYi build due to its powerful passive.

No, not that one. The other one.


Yep, that's what I'm looking for. It basically means that for every third AA, Guinsoo Rageblade can double every on-hit effects like your Blade of the Ruined King or Wit's End. It's even better on Master Yi, since he has 3 things that can interact with Guinsoo: Master Yi's E, Master Yi's Q, and even Double Strike. It applies 2 times True Damage with Wuju Style, reduces 2 seconds on Q cooldown, and add 2 stacks on Double Strike!





Navori Quickblades is an item that needs no introduction. This item causes your basic attacks on-attack that critically strike reduce your basic abilities' cooldowns by 20% of their remaining cooldowns. On top of that, it also gives you 30 AH and 20% Critical Rate.







Not a fan of Maths? Skip to Runes and Items

To summarize, how can we reduce Master Yi’s Q cooldown to 3 hits, again?

Ooh, and there is one more thing. Remember that while you are casting Q, the cooldown of this skill doesn’t freeze, but it counts down by 1.089 seconds at full Q duration. With this small time frame, it also reduces your Q cooldowns immediately after Ability Haste is applied.





With all knowledge we have, let's make our basic formula:



Looking at the formula, building Attack Speed increases the divisor of 1 => reduces the time interval between attacks => which make the final result higher => mathematically incorrect. Right?

Of course not! Attack Speed is a vital part of Master Yi's DPS and we must build our Ability Haste around it. So, on the next part, we will set our Attack Speed to 2.0. Why 2.0 Attack Speed? It's a reliable amount of Attack Speed that Yi can easily achieve with Highlander and Attack Speed keystones (HOB or Lethal Tempo), yet you won't always reach 2.0 only via MCMYi itemizations. Besides, it's also easier to count.

Our formula will turn to something like this:






With our basic formula, how many Ability Haste do we need to reduce Q cooldown to 0?


162.7689276 Ability Haste. Wow, that's a lot of Ability Haste. Is it possible to reach 162.7689276 Ability Haste with your runes and items? Of course. But is the itemization efficient? Of course not. Let's try another way.




For example, if we add Guinsoo's Rageblade to the build, the formula will be something like this:


Replace Attack Speed with 2, and the formula will turn into this:

Now, how many Ability Haste should you build?



Much better. 97.7994808 AH is completely possible. You can reach it with runes and items while still having some slots for flex items.




But can we make this number even lower?


Absolutely! With Navori Quickblades + Full Crit build, and the formula will be something like this:




Once again, I'm sorry for the lack of mathematical formula for Navori Quickblades build please forgive me uwu. However, if you want to see the minimum Ability Haste you need for this build to be 'mathematically correct', I have done the calculations for you...





65 Ability Haste. That's right. You don't need to build full AH, just 65 AH + Full Crit is enough.


Now that we have gotten the hang of the maths and made mathematical calculation on all kinds of MCMYi builds, let's go to the part we all are here for:



And there we go! Finally, we have arrived at the runes and items section. Or maybe you skipped here via clicking from the Table of Contents? (do you guys know you can do that?) Either way, let's talk about the runes and items we're going to use on our MCMYi!

DOMINATION	or	PRECISION
Hail of Blades		Conqueror
Hail of Blades maximizes Master Yi's frontloaded damage potential. Works extremely well in assassination (Duskblade build) and setting up your Guinsoo + Double Strike combo. You can also take Electrocute but HoB has higher damage and value, especially on Master Yi.		Conqueror excels at long trades. Works very well in maximizing Master Yi's DPS, giving you extra True Damage from E (and Kraken Slayer) while also providing you with extra sustain at full stack. You can also take Lethal Tempo or Press the Attack but people usually prefer Conqueror for higher sustain.
Sudden Impact		Triumph
Sudden Impact gives you Lethality simply by pressing Q. You can also use Taste of Blood if you play him in lane.		Triumph gives money and healing after takedown. Very good for Yi jungle.
Eyeball Collection		Legend: Alacrity
Honestly, all runes in the third row of Domination rune does the same thing: giving extra damage, but Eyeball Collection is just the most commonly picked rune.		All of the Legend runes are viable on Master Yi. Alacrity for Attack Speed, Legend: Tenacity for, well, Tenacity, and Legend: Bloodline for Life Steal. Pick whichever suits your game plan.
Ravenous Hunter		Last Stand
Ravenous Hunter is the most commonly used due to Omnivamp. You can also use Ultimate Hunter for that spicy Ultimate Haste, but MCMYi already gives you a lot of Ability Haste anyway.		Last Stand if you like to win trades at low HP, Cut Down against tanks, or even Coup de Grace if you don't like being at low HP. Again, pick whichever suits your playstyle.

Itemization on MCMYi will be efficient for reducing Q cooldown to 3 hits if you craft your build path around one of these two items:

1. Guinsoo's Rageblade, due to Guinsoo + Double Strike combo. This build path will be focusing on On-hit Effects, which Guinsoo's Rageblade excels at, while still giving you a lot of Ability Haste.

2. Navori Quickblades, due to Navori's passive. This build path will aim to reach 100% Critical Strike Chance while giving you enough Ability Haste to pull off your MCMYi.




With On-Hit Path: Guinsoo's Rageblade, our goal is to build 97.7994808 Ability Haste, rounded up to 98 Ability Haste. To achieve that while still maximizing the build potential, here is the build path I find effective:

1. Mythic Item

The most favorable first item is Duskblade of Draktharr. It will give you 20 AH and 5 more AH for every other legendary items. Also the takedown invisibility yeahhhh. Goredrinker also gives you the same amount of AH but is more rarely built on Yi.

2. Complete Your Boots

I heavily recommend using CD Boots if you are aiming at MCMYi. However, it's also good to use the other boots situationally, for example: Berserker's Greaves for maximizing DPS and gold efficiency, Mercury Threads against AP/CC/both, Plated Steelcaps against full AD comps.

3. Guinsoo's Rageblade

A very important item for DPS. Master Yi is one of the champions that can build this item early on because you will activate Master Yi's Guinsoo + Double Strike combo. This combo will also shorten your Q cooldowns while doubling your true damage. With these two core items + boots, you can reach Master Yi's powerspike

4. Pick one item with strong On-hit Effects

Due to the Guinsoo + Double Strike we got earlier, all of your On-hit damages are doubled, so use this to your advantage and strengthen Master Yi's powerspike with items that can apply strong On-hit Effects. Ideally, we pick Blade of the Ruined King against majority of enemy comps and Wit's End against magic.

5. Pick 1 Ability Haste item with at least 20 AH.

These are several 20-30 AH items you can choose. Black Cleaver is the most recommended item, since it gives you 25 AH, damage, team armor pen that you can stack very easily because you are Master Yi, and a bit of tankiness. In 20 AH items, we have Essence Reaver for Sheen effect which MCMYi can utilize very very well, Serylda for utility and armor pen, Ravenous Hydra for dat spicy Omnivamp. Navori Quickblades gives you 30 AH but you will 'miss' the passive since you can't crit. If you built CD boots and Black Cleaver / Navori, congratulations! You have reached at least 98 Ability Haste (18 AH from runes + 20 AH + 15 AH Duskblade Mythic passsive + 20 AH + 25 AH) and you are now a Mathematically Correct Master Yi!

6. Pick 1 flex item

Alternative path: You can replace the Strong On-hit Effects item with The Collector, and build it before Guinsoo's Rageblade. That way, you will activate the extremely powerful Duskblade-Collector powerspike, very good against squishies.






The Full Crit Path is much easier to follow. You only need to achieve 65 Ability Haste to create MCMYi instead of 98. The item guide below functions more as guidelines instead of itemization order, because you have full flexibility on what you want to build (mostly due to its nature of being Crit build, because your usual goal is to gain early lead -> deal tons of damage and adapt to situations -> scale to late game).

1. Navori Quickblades Is Your Must-Build On Late Game

30 Ability Haste, 60 AD, 20% Critical Rate, what else do you need? Gold. 3400 Gold is so expensive for an early item. Furthermore, your Critical Rate is still very low, you can't bring its passive to maximum power. Build this on mid to late game.

2. Pick One Of These Two 20 AH Items

Essence Reaver has Crit, 20 AH, and Sheen. CD Boots has 20 AH and take Boots slot. Choose only one of these, because assuming you use MCMYi runes, you now have 30 + 20 + 18 AH = 68 AH. If you have 100% Critical Rate, you are now Mathematically Correct. If you use standard Yi runes, however, you have to build both of them and you will still become Mathematically Correct due to having 70 AH. You don't even have to use MCMYi runes! Why 68 AH? Why 70 AH? Why not 65 AH like you stated earlier? Because there are no crit items with 15 Ability Haste. Forcing to build 15 AH items will make the build more awkward.

3. Crit Items? Anything You Want! (Except Guinsoo's Rageblade)

etc.	For other items on Navori Path, pick any of Master Yi's Crit Mythic and Legendary items according to your personal build path, liking, and situations! Feel free to build anything you want (except Guinsoo's Rageblade) as long as you reach 100% Critical Rate for that mathematical correctness!

Honestly, I don't know a lot about Master Yi's gameplan. Tips for early, mid, late, when behind, when ahead, etc? We don't do that here. This part will be focusing on simple mechanical tips and combos (or rather, Mathematically Correct tips and combos).

Mathematically Correct Combos

1. As a lot of people already knew, you can use Meditate to reset auto attacks. This is very inefficient in combat, however, since you have to AA -> cancel to W -> right click to cancel W and AA again.

2. The mathematically correct combo if you use Master Yi with Lethal Tempo is AA on enemy champion -> Q, and after a short moment, your Lethal Tempo is fully charged up. This is also the reason why some people don't like Lethal Tempo Yi since you usually engage with Q.

3. If you use Guinsoo, auto attack at least twice anywhere before going in with Q, then all of your next auto attacks will apply Guinsoo + Double Strike (AA > AA > Q > Guinsoo > DS > Guinsoo > DS, etc.). If you use Navori, auto attack at least once instead so you can activate Double Strike within your next 3 auto attacks (AA > Q > AA > AA > DS > AA, etc.). These two setups allow you to do by-the-book Mathematically Correct combo as seen in the formula in Maths section.

Mathematically Correct Tips

4. When you have activated Guinsoo + Double Strike combo, every 2 attacks will apply 3 On-attack effects and 4 On-hit Effects. With this setup, you can technically turn Kraken Slayer's Bring it Down to 2 attack passive instead of 3!

5. When you Meditate, you gain charge of Double Strike. When you Meditate to full DS stack while equipping Guinsoo's Rageblade, you instantly activate the Guinsoo + Double Strike combo.

6. Master Yi's Alpha Strike can only follow up-to 2000 units; if the target teleports a very long distance (e.g. Stand United) it will not be followed.

7. Never build Guinsoo's Rageblade in Full Crit Yi build. The main reason is because your Q will not crit anymore. The second reason is you will mess the MCMYi Navori Path since you have to build 98 Ability Haste like Guinsoo Path instead of 65.