I decided to create this build for one of the most scary fed champs in the game, that is the invincible Master Yi. Master Yi was the first champ I ever played and will always be one of my favourite AD carries. This guide will not include a jungle section as I believe Yi best shows his talents in a lane. This guide is the outline of what I do EVERY match. Don't bomb me down either, i ask that you merely try the build out and give me POSITIVE feedback on what you believe i need to change. I know in this build I will completely explain what and why, don't get annoyed if your are a vet player, this is for people who don't have much game play concepts. And Thanks for taking the time to read my guide/build.

First time so be nice =)

Keeper of the ancient art of Wuju, Master Yi is a mystical warrior from the isle of Ionia. He descended from one of the few tribes dedicated to the preservation of Wuju, a martial art founded with the principles of absolute spiritual awareness of one's self and one's enemy. When the armies of Noxus invaded Ionia, Master Yi joined in the Ionian defense to fight the craven enemy, bringing his village honor through his unparalleled mastery of the blade. The ensuing battles ravaged the land, but no conflict inflicted as much horror as the day the armies of Noxus closed in on Yi's village. Left undefended, the village became the unfortunate test subject of the latest invention by an up-and-coming chemist, now known as Singed. The remains of the village that Master Yi returned to were so horrific that it remains a festering scar on Ionian history. To this day, no Ionian will ever publicly speak of what occurred.

After the Noxian invasion was contained, Master Yi fell into a deep isolation. For years, he trained morning to night, speaking to no one and refusing offers of consolation by fellow Ionians. The only thing stopping him from madly charging into Noxus battle lines headfirst was his pledge to keep the Wuju style alive. Even though he seethed with impatience, his rage became a tool for sharpening his practice of Wuju, developing stronger and deadlier skills for his eventual vengeance. The only thing that roused him was news of the League's formation, and Noxus' subsequent enrollment in the League. Master Yi now brings his mastery of the blade to the League of Legends with unflinching purpose: to avenge his kinfolk and end the predations of the Noxus once and for all.

The video below utilises all of Yi abilities and shows you how the should work. Notice at the end he hits a mushroom and survives it with a meditate =) Play Video

Pros

+ Amazing farmer whole way through game.
+ Simple champ and easy to learn.
+ Great lane stability with life steal.
+ Insane amount of damage mid/end game.
+ Can jungle with ease any time.
+ Can carry an entire team if fed.
+ Great escape mechanism's.

Cons

- Not that great start game.
- Focused to an insane extent.
- Raped by CC effects(Stuns, fear etc.)
- No CC at all.
- Mana problems early game is they are spammed to much.

The build i have used countless times is perfect for any normal match, but if your having problems you may need some situational items.

Start/mid game problems
These usually are Hp problems and are rarely damage in any case i have seen, if you are having survivablity issues i advise getting aphage, it gives some health and a 1/4 chance of slowing your prey down, what more would yi need?

Massive cc / Casters
If you are having a problem with this kind team i highly recommend gettingbanshees-veil. This will give magic resistance and block the first offensive spell cast upon you allow you to receive NO damage or effect, it can save you with enemies like-
~~~~~~~~
Annie
Alistar
Nasus
Lux
Malzahar
Karthus
Ryze
Amumu etc, The list is countless, a sexy item for Yi.
~~~~~~~~

Guardian Angel
If you getting Op and are getting picked off early fights this is the perfect rebirth item. In addition to its magic and armour resist its a nice item.

Last Whisper
Good if you are playing against tanks with high armor.The 40% Armor Penetration great.

Wit's End
You are playing against AP team and you want some extra MR and AS.

For summonor skills i have went with the most simple and effective solution, that being -

Flash

And


Exhaust

Just use these spells to maximum effective need and only when needed, the main thing most Yi's do wrong is use an exhaust on a target beside the tower half Hp, dont dive at low lvls and don't waste a perfectly good exhaust. Furthermore im not going to go through what you shouldn't get like most guides do, its a waste of time and common sense should guide you =) It brought you here =P

I choose the basic 21 - 0 - 9 as it maxs damage output and ensures the maximum amount of experience received in the smallest amount of time. Pretty basic stuff =)

Double strike
This is yi passive and one of the best in the game for an ad carry, you hit twice every hit strike you land. Image maxed hitting 1k critical damage and doing it twice? Ill let your mind wonder over that abit . . . and we move on.
______________________________________________________________________________________________
Alpha strike
This is Yi's most spammable and easily annoying to move that will allow you to both catch prey, farm, or even get away. This ability will be your main harrass tool early game, as it gives aoe strike damage to the opposing team.

Uses
+ Farm like @&*!.
+ Catch up to your prey.
+ Harass enemy players.
(The ability is based on magical damage and will not have much effect later game.)
______________________________________________________________________________________________
Meditate
This ability allows yi to channel his energy to heal himself and gain magic and armour resist. This can be extremely useful laneing early game as you may be unmovable in any lane, Many Yi's get the straight off the bat, but i believe your Life steal is enough to allow you to lane with confidence and not waste precious many that could be used to farm.
(Again with previous ability, this loses its effectiveness late game as it runs off Ability power.)

Uses
You know that karthus loves his ulti (mother of a toaster), use meditate when this happens to both obtain health and resistances, this will leave you free from death, use this when running away with ignite or an ulti such as mords. (Death is for the weak).
______________________________________________________________________________________________
Wuji Style
This ability is Yi's bread and butter, this ability will obtain you massive damage output start game. This ability will add 35 more attack damage passively and add 70 attack damage when activated.

Uses
The main use of this is obvious, to obtain extra damage early on and allow you to max attack speed and not even notice the lack of attack damage until you get your bf sword.
______________________________________________________________________________________________
Highlander
This ultimate is the reason many people have nightmares after a Yi match waking up sweating screaming his name in bloody murder.

Activation
(People will start running)
- Yi's ultimate when maxed will improve your attack speed by 80% for 12 seconds with increased movement speed, good thing you can catch up now.
- Instant immunity to any sort of slowing affect! This means no exhausting that freak train.
(*Sings* Nowhere to run to nowhere to hide!)
- Last but not least, when you finally catch your prey (i cant call them anything else) and nuke him down with my build in like 2 seconds, the cooldown on your ultimate is reset, and with a mere ***sit it is halfed! This only works within the 12 seconds so ensure you have your work done at a reasonable pace within the time allocated.

There are a range of things you can do with this ulti such as \/

1/ People WILL start running for their lives.
2/ You will Obtain 80% attack speed(maxed), wow when you catch him is he dead.
3/ Increased movement speed, good thing to because they are running pretty fast.
4/ Amazing escape mechanised, as when it is activated you are immune to any sort of slow effects, Yes that's right no exhaust to get this swordmans (He works out to much)

Movement speed increase + flash = GTFO LOL

Side note - when you kill an enemy you will have a refreshed cool down on your ultimate or 50% reduction with an assist.This leaves Yi with little to no cool downs if you can kill your prey fast enough.

You - So, i can still have my ultimate after that team fight with just 1 kill, not even mentioning the assists? So that mean I can chase anyone who is fleeing?

Me - Is butter made of Milk?
______________________________________________________________________________________________

Ok now for the skill sequence. As always you will want to harass with Yi's Alplha strikeAs much as possible. This will allow you to not only farm creeps effectively at a distance but disorient the team. Pyscologally it does wondors to people who believe they are safe when you come zooming in out of nowhere and do a small amount of damage to.

Remember, where you cast aplha strike is where you will land, so make sure it is a minion closer to your side of the map, the aoe strike will go after all surrounding minions anyway so dont worry.

After level 1, you will see that i get Wuju Style flat, this is because you will want that extra damage AS SOON AS POSSIBLE. This will mean you can play aggressive and know that you will have a massive chance at First blood with this abilities extra buck, that shouldn't be a problem. But remember keep farming with that Alpha strike!

Ok now I have went over all the abilities a and pros/cons of Yi, you want to play him straight away right ? From this part of the guide down I will be explaining how to play Master Yi to his full potential.

Before you even head to a lane blindly think of who you should be with. You want some range to cover you and allow you to farm aswell as being given the ability to kill your prey at level 6. The perfect champs for this is basicly asone with a stun or strong CC's all around. Champs like . . .

Good laners with Yi
Morgana
Alistar
Annie
Lux
Malzhar
Maokai
Ryze
Kennen
Swain
Sion
Ashe

Acceptable Laners with Yi
Rammus
Leona
Twisted Fate
Twitch
Miss fortune
Orianna

Bad Laners with Yi
This part could fill the rest of the guide, anyone not mention you shouldn't lane with, Yi wont need a support as your life steal will sustain you the whole way through the start game laning phase. It isent advised he lanes with people with no range, as you will not have the ability to farm to your max extent without a ranger controlling your lane.

-Side note-
You are slightly squishy start game so be careful. Keep this in mind with the fact that you WILL be focused in your lane.
-Side note-

Start game is all about you reaching level 6 and getting as much gold as possible, remember, this is Yi's strongest ability, even if the enemy team are playing safe you caan farm with the best in the game playing as Yi, at the end of a 20 minitute game you should have at least 150 minions killed. Just play peaceful and harass the enemy while farming until you get level 6.

If your having trouble
If your having serious trouble in your line you have to considering doing a few things.

1/ Switching lane - Yi can cut squishy s in two, this can be done in an effective and swift fashion, so laning against 1 tank and 1 off tank start game, will let to massive problems, ask a beefer team-mate in the opposite lane to switch so that you may get more fed. Remember your going to be the AD, you are one of the most important members of the team, a fed tank cant do much.

2/ If all lanes are having problems, you may have to jungle, Yi isent the best jungler in the game but can do it moderately. Remember to ask permission to leave your lane and ensure your jungler (if you have one) doesn't mind you having a jungle run.

You've reached level 6, now is the time to kill. Due to your harassing start game the enemy should have half health and little farm, because of this if you should go back at level 6 get your items and head back to destroy any left in your lane, they will take advantage of you not being there to stop there farm, little do they know they should have went back and got full hp.

Come back through the side bush and let your partner land a stun, patience is key. As soon as it has landed jump in with alpha along with Wuju and Highland and cut the enemy to piece's any escaping enemys should be exhausted and finished off accordingly. This is how to attack every time.

Now that your lane is cleaned up you may now do one of two things.
1/ Jungle getting red and blue buff.
2/ Go gank other lanes, remember, yi will be alot more effective if you do step 1 first. Red buff slowing your prey with your increased movement speed slashing at them should mean a quick kill.

If your having trouble
If your having trouble mid game, you have have to do one of three things.
1/ Farm more in your lane. As mid game tends to lead to a fight off in the middle that isent going anywhere, ask your team-mate if they are planning to fight, if the response is no go farm and push a tower if possible, people will be focusing on mid and considering your team mates a free kill, little do they notice you taking towers like a boss.
2/ Get dragon! If it isent already taken, ensure you get the maximum amount of gold
3/ Jungle! You can always do this.
4/ Try to gank other lanes more.
______________________________________________________________________________________________

This is where Yi shines the most. With even half your full items, you can take down towers in 3 - 6 seconds with a little help from your ultimate. This leaves to a destructive tool to be reckoned with. You should push towers, farm and gank to the max extend. Remember any teams fights going down get there ASAP. You WILL be the biggest damage dealer of the team so its vital that you make an appearance, don't just show up at the last second finishing anyone with low health like i see many ad carries do, it just dosen't work, you will get one kill and end up with your death leaving your towers undefended.

Thinks to considor
1/After you have your core items (shown below) you will be able to take almost anyone but dont make a common mistake when fighting with Yi, "Attack is your best form of defence" Remember this saying, as your blood thirstier will give you a mass amount of HP back, even fight two people at once.
+ Frozen mallet
+ Infinity
+ Blood thirstier
+ Phantoms

2/ You are the main damage and WILL be focused! Be careful where you go with any support. If you die in mid out of position your team mates will follow. Go in AFTER the tank! Count to two after the tank has started the team fight.

If thinks are going bad
1/Baron, pretty simple, if you have core items you can kill dragon with only 1 other person. This can get you a sneaky baron kill and help your team to victory
Enemy players - "Nope barons ok, sure 3 of them are defending, (pings baron) lets go for it. Wait waaaaa?!!? Its gone?!!?!?"

You "Muhahahahahaahahah" (And you kill them all) =P

2/ Get all your team the suitable buffs for themselves and allow under farmed players to get up a little, give your self room for error push all lanes as you will be going thought minions like water and then all push 1 lane together, even if you all die(which, with a Yi, lets be honest here), they will have to push the minions waves back to get to your towers.

Team work around the whole game should be focused around everybody doing there jobs and being looked after, to many AD carry's are selfish and take all gold, buff etc. They leave nothing for others, let others have the kill if you are starting to get fed, remember your important but so are your team, Work with your tank and ensure he gets as much aggro from the enemy players as possible and go in, to many Yi's i have seen run in blindly getting nuked i quick succession, @!&^ that, you need to down some peeps with minimal damage to yourself.

Get some wards! This is key in any game, just because you are the carry, its not your job to complain to others about the lack of wards, if your getting fed get some yourself, playing normal your going to get people who don't want to help someone who is complaining, be nice to your team and they be nice to you.

Remember you will nearly always be the main damage NEVER EVER leave a team fight you "Think" you might lose get in there are stomp some of their biggest AD carries and you alone can turn the tide of battle, master swordsman or not, don't be a pu$$y, Yi is all about defying the odds of Lol.

Always give CONSTRUCTIVE crit to anyone having problems, we all have bad games don't just start blindly complaining and blaming 1 players by saying stuff like "Go uni stall noob", its your fault if you are losing as well. Think what the problem is and try to resolve it, why is the support - 5? They are getting to focused try and tell them to move their position so they are better protected.

"We live together we die together" - This saying is mostly true in league, allot of people make this game hard to play sometimes, if we all give some good advice and diden't complain, we would all have more fun, the game is about having fun, never forget that.

Overall, I believe Master Yi is a fantastic champ who is played well can very well be unstoppable. If you want a champ who can truly carry a team and even solo baron then play Yi =)

Yi only being 450 IP means he is a very viable champ for anyone * Murmurs* Get him get him, vote them guide up * Murmurs*

Remember the game is all about fun, Just remember to have it and not take it so seriously.

Peace out guys have fun trying my guide.