Hey guys tjLOL here with a guide for master yi. I have been playing for 1 or 2 years now, and master yi was my first champion i ever played. He was my favorite, and still is. I always jungled. And now, when you first try this build, it wont do good or great, you'll start the game 2 and 4, but sometimes you'll go 9 and 1, depending if you're greedy or not, so if you dont do good first, keep going because its supposed to be a even build, not 100% cheap kick *** (it still kicks *** though)build, but made for fun.
heres some pros and cons of this build, and yi him self as a champion.
Pros
-good DPS rate
-good movement around map
-easy to jungle
-ultimate mixes with ghost blade to make it better
-60 second cool down

Cons
-easily focused
-always slowed by other characters
-easy to harass
-not the best against magers

The diffrent builds are
1: normal
2: jungling
3: anti tank

]Why these rune you might say?
Greater quintessence of strength- straight up DPS
Greater mark of desolation- This is optional, it chews through tanks, and does even more base damage. if you'd like, make it a mark of strength, but is preferred if you use desolation marks.
Greater glyph of warding- this is a weird thing for some people, because yi isn't a tank, but this is really needed, or optional! yi is extremely easy to be killed by fiddlesticks, or Morgana, or Veigar. this helps EXTREMELY in the early game, to make it easier to kill them, for feed. if you don't want this, then grab mana regen, or attack damage each level, Preferably mana regen since yi is extremely mana dependent in the early and mid game.

The masteries are normal... no explanation needed.

boy oh boy here we go...

Early Game

Dagger to begin with- Why? so its easier to get a kill for feed, same with Long Sword.
The Brutalizer- why have this in the early, not mid or late? because cooldowns are annoying, and gives more damage, 25 mixed with any of your E's damage and quints are amazingly powerful.

Middle Game

The Bilge Walter Cutlass- This is simply AMAZING! it will give life steal, and attack damage, AND slow down the enemy while dealing damage! it is all together AMAZING! it is perfect for yi, especially for the damage and slow down.
Hextech Gunblade- This is an amazing item. it is perfect for AP, AD, Slow, and lifesteal. these are some of the main things master yi needs to survive. AP help with alpha strike, ad help with everything, slow for ganking, and life steal for survival ability and jungling. the damage from the active is also really helpful.
Bloodthirster- sexy... look at the picture! ahemm.. i mean this is really helpful also, the damage is perfect for DPS and the lifesteal commences more time in the heat of the war.
Youmuus ghostblade- this is and extremely underated item. when i first played yi, i didnt see the point, so just grabbed sword of occult *which is understandable and great for yi if you dont want yomuus.*, but then i found out who to use the active and oh god was is fun. mixing with you're ultimate,if will be a kill in a instant. if you have you full build, it will likely be a 2-6 hit kill.

Late Game

Infinity edge- Good for 250% critical damage and more AD... not much more to say about it...
Phantoms Dancer- Amazing for yi! more attack speed, and movement speed AND crit chance! really needed in a build!

Situational Items

Tanky team?
same build but instead of phantoms late game, mid game last whisper, it'll help, but if they have high health, switch out youmuus with madreds bloodrazers for devastation to their health.
AP team?
basically same except for mid game get a quick silver sash. This item is EXTREMELY under used!
it is perfect for any tank, or even AD/AS carry.
AD Fed team?
get a mid or late game Thornmail. it is very helpful with armour, and 30% reflected basic damage to the enemy, helping kill them easier, while you're saying "stop killing your self" the whole time.... hahahah....

This is possibly the weirdest part of the build.
Ghost- WHAT WHY, ISNT HIS ULT GHOST!?!?
yes... but for the first 6 levels do you have an ult? no. what if its on cool down, it really helps dramatically, and can even mix with the ult for hyper speed. if thats not enough, while your ult is out, it helps turret dive effectively, so when it ends and your stuck in the turret, just hit D/F and run out of there.
Ignite- really helpful, last hits, and can save you a free ult cool down, especially when your ghost is on cool down, and can't turret dive.

Jungling, really good with yi since alpha strike can critically hit minions.
Make sure you start with armour and full health pots!

Pros and cons of yi jungle

Pros
-easy gold build
-easy gank
-minion feed
-easy buffs
-map control
cons
-item differentiation
smite wastes either ghost or ignite
build- just change cutlass for wriggles lantern

FOR EARLY TO LATE GAME, THEN SELL AND GET THE FULL NORMAL BUILD!

YOU DO NOT KEEP IT THE WHOLE game unless they surrender! this is extremely important, as yes it is free wards, but you will be making enough money by ganking to get wards.
path: Golems first
first, Q them, finish em, should maybe use a health pot.
wraiths:
smite the head wraith, then finish this little ones, maybe a health pot or 2
wolves: proceed to kill them
repeat this till level 5 with your wriggles, and get blue then red buff, and keep ganking between levels 2-18.

Masteries for jungling

diffrent, but normal for any jungler.

Team work, the most important thing in the game. NEVER forget about teamates, and say sorry for kill steals and such, but before ganks, PLAN THEM! if you have your cutlass, run in slow them and commence using q and e, but possibly not your ult, as you most likely will not need it, or get the kill. when done, proceed to recall and go back to your original lane, or jungle.
During teamfights:
this is really the most important part of any fight, team fights are always going to happen. heres how it should happen: tank goes in first, dps goes in next, ap stays back casting spells.
if you run in at first on accident, heres how to play it out:
ping a squishy enemy for your team to focus
get away from stealthy champs such as Twitch, Akali and Teemo
and use your q,r,e and attack. if failed, you still did alot of damage with you q, no matter what items and your level, it helped. pat yourself on the back
if you won, you and your team either...
1. push
2. baron
3. recall.

In ranked play a carry is needed 100% of the time, and Yi is perfect for it. This build has been used in ranked, and I've played tournaments with it, and it keeps me steady the whole games, unless i was to greedy at 1 time. the difference is with yi, the skilled enemies will know what you're building, and attempt to counter it, counter their counter by justing getting a armour penetration item with yoummus also. the best i could help....

build 1

Regular build with a twist of hybrid in it... no explanation needed

Build 2

Jungling build, to normal build, no explanation either...

Build 3

tank crusher build. the differences in the build is armour penetration, and a small amount more damage. :]

Build 4

THIS is a extremely weird build for some people, for others it makes alot of sense, This is mr op, kick your *** in 3 hits, build. i dont like it much, since it is just boring to play as.

build 4: (all in 1 game)
Triple
Double

thank to all my friends who helped with this guide!
David
Drew
Andy
and Kyle :D