Flat MR in Glyphs (for some reason not available in Mobafires gui) and flat Armor in Wards. Simply because they are what I have found overall best to help you live through that brief CD on your Q when you're getting focused.
The flat AP quints are perfect for yi to maximize his early healing with meditate, before you are able to build any AP.
The Magic Pen Marks are simply there to counter the base MR of your opposing champion. Almost True damage. feelsgoodman.jpeg
I do the simple yet effective 21-0-9 mastery build to maximize early AP and Magic Pen along with increased damage overall. The 9 in Utility for that extra movement speed and mana is what saves you from being hit by that Lux ult or Morgana stun, along with one more meditation worth of mana that could save your life.
Now, the thing people want most. The item build.
AP Master Yi focuses on being a glass-cannon with his tankiness being him being pretty much unkillable during Meditation. We are therefore completely ignoring defensive items.
We start with Boots of Speed, simply to give you the movement edge over your opponent during early game, which have often saved me from ganks. The Health Potions are very helpful aswell, until you've gotten your Meditate.
I then finish the Sorcerer's Shoes. "But 44tim44, why dont you buy an early Blasting Wand instead?!" Well, simply because Movement is Master Yi's calling card. Besides, lowering the enemy MR can be just as offensive as buying AP.
Now, for the more sketchy part of the build. The Doran's Ring. This item I usually don't get, unless I'm losing in mid or are having a hard time farming. The Mana regen and Health is a great addition, but if possible, skip and go straight for the Deathcap.
Rabadon's Deathcap Do I even need to explain?
Here comes the next very important item. Lich Bane Since you have a pretty long CD on your Alpha Strike, you need to be able to still do damage. Hence, the Lich Bane. Alpha Strike to an enemy and hit them with 1 basic attack, then retreat. REPEAT.
After that I usually go for a Morello's Evil Tome if I get that far.
AP, Mana Regen and most importantly Cooldown Reduction. We need to be able to use Alpha Strike more often.
OTHER VIABLE ITEMS
Cooldown Reduction, and an active to use on the enemy during those Alpha Strike Cooldowns. Can be very effective. Usually the item I buy after or instead of Morello's Evil Tome if need be.
Cooldown Reduction, some Mana and Health Regen along with an Active for quickly getting the hell out of a battle or storm in guns blazing. I do find this item a little too defensive to suit
Master Yi though. Master Yi rearely runs out of Mana aswell, and the Health regen is unnessescary since Master Yi has his Meditate. But if you have trouble staying alive early game, definitely go for this one.
Usually, you heal more than enough with Meditate, BUT. If the enemy team is strong with AP, definitely go for this one. It makes you even more unkillable when you tank using your Meditate. And that extra Magic Resist can do wonders.
If the enemy starts building way too much Magic Resist because they realize you are OP, definitely go for this one. I usually take this before Morello's Evil Tome when I do.
Can give you the edge against champs like Kassadin, if he silences you after your Alpha Strike and forces you to fight him. The Active can be what's needed to finish him off before he finishes you off, and if you do survive, your Alpha Strike will heal you up again, helping you if more enemies are incoming.
If you are getting bursted to death by LeBlanc after you have used your Alpha Strike in a team fight, this one might be for you. Gives you an unkillable state while you wait for the cooldown of your Alpha Strike.
Also good when facing an AD-heavy team, because of both the armor and the active.
Play Style and Summary
The basic playing style of Master Yi in the mid lane is this:
When the enemy get within, Alpha Strike and run away. (One basic attack aswell if you have gotten your Lich Bane.)
Your speed makes you unchasable and the burst damage you do can be enough to make them go away for a bit, but they'll be back.
If the enemy is smart, and knows you can't do anything while Alpha Strike is on cooldown, they might try to go for you and turret dive. When this happens, simply hit them once with a basic attack, press W, lean back in your chair or sofa, and let your turret do the work, while you tank their attacks. If need be, finish off with an Alpha Strike.
OH SH*T! The enemy managed to slow you under their Turret whatever will you do?!
Press W. If you at least have a Needlessly Large Rod, you'll probably be able to outheal the turret's damage, and then get away safely. If stunned: You're ****ed. That's the main downsize of AP Master Yi. He is very easily killed if properly feared/stunned/snared/silenced.
Don't worry though. Most of the time, you'll survive with 10% Health, and that is more than enough for you to Meditate, and then Alpha Strike them to death, or run.
Meditate is your best friend in a team fight. Always make sure it is available before entering, or you might die. I once became the center of attention when an enemy Kennen used his ult. I simply pressed W and I had more Health than before his ult.
Playing Style Summary: Stay back, use Alpha Strike with you can. Avoid being focused and use Meditate when you do get focused.
Match histories: (More will be added)
Expect Triple Kills and people raging at you for taking their kills. They'll be sorry, when they see you bursting 4 enemeis down to 33% Health in one Alpha Strike late-game.
I hope you enjoyed my build. Upvote if you did.
Comments and critique is appreciated.