Just another Yi guide. not really good but i`m such a pro.
this guide includes fail grammar, non-in-depthness, aznstyl0r and some wordspam to have 5000 letters.

Have Phan! :D
~

some standart jungling/melee runes
Greater Mark of Desolation ArPen marks
Greater Seal of Armor Armor seals
Greater Glyph of Scaling Magic Resist MRes glyphs
Greater Quintessence of Attack Speed AS quints
Greater Quintessence of Desolation ArPen

21/9/0 MOAR DAMAGEOUTPUT!!!!!!!!!!!11!1eleven!! and a little bit more tankieness

UPDATE I dont know how to spent the new Masteries on Jungler but i've tried my best to do some possible tries.

Double Strike
Master Yi strikes twice every 7th attack.
-Great Passive, it can be used for tower killing to dealing massive burst damage at low levels. Your FirstBlood tool.

Alpha Strike
Master Yi leaps across the battlefield striking up to 4 enemies, dealing magic damage to each enemy with a good chance to deal 400 bonus magic damage to minions.
-Great Skill for catching up to an enemy and for farming.

Meditate
Master Yi channels, restoring health over 5 seconds. While channeling, Master Yi gains armor and magic resistance.
-underrated skill..gain +100 armor and mres at lvl 1. take it with lvl4. it will safe your life very often.

Wuju Style
Passive: Increases physical damage. (Active): Master Yi can activate this ability to double its effectiveness for 10 seconds, but this removes the passive bonus until Wuju Style becomes available again.
- +30ad with lvl 1?!?! what the heo?

Highlander
For several seconds, increases Master Yi's speed of movement and attack by a large percentage, plus makes him immune to all slowing effects. Additionally, killing a champion refreshes all of Master Yi's cooldowns, and scoring an assist reduce the cooldowns by half.
- +as +ms +immune to all slows. what do you need more?

just a item build i test for a long time
jungle:
start with Cloth Armor and 5 Health Potion (if your advance with only 3 Health Potion). continue with Madred's Razors and finish Wriggle's Lantern or if you want to gank with Boots.

lane:
start with a Long Sword or Boots and some Health Potion. rush Youmuu's Ghostblade asap and skip Wriggle's Lantern.

you should have your Youmuu's Ghostblade at least at 15minutes, if you start with Wriggle's Lantern with 20minutes.

for lifesteal replace Wriggle's Lantern with Bloodthirster.
if youre cool sell your Mercury's Treads for another Phantom Dancer / Guardian Angel / Trinity Force or Madred's Bloodrazor as the last items.
you should have enough movementspeed with Highlander, Youmuu's Ghostblade and Phantom Dancer.
Phantom Dancer - more damageoutput
Guardian Angel - for more tankieness
Madred's Bloodrazor - many many tanks or just some stupid hp stackers
Trinity Force - be a wannebe pro

this build is quite expensive (~25k gold). you have to farm a lot. but after your Youmuu's Ghostblade you should kill everyone easily.

this build can be also used for dominion.

And for the pro`s:
Malady Mondays
Tiamat Tuesday
Warmog's Armor Wednesday
Thornmail Thursday
Frozen Heart Friday,
Sight Ward Saturdays,
Sunfire Aegis Sundays,

or the ultimate bravery
http://www.giantfunny.com/ultimate_bravery.php

epic jungle route by Mr.Jungler stonewall008

you are best teammate evah! wait for your team initiate. after the enemys cast all the deadly skills and your team died, initiate with Alpha Strike --> Wuju Style --> Youmuu's Ghostblade --> Highlander and just wait for your pentakill. try to activate all your skills at the same time for instant high damageoutput

i took Ghost cus Ghost + Highlander + Youmuu's Ghostblade + Phantom Dancer = over 9000 movementspeed
and youre not a Flash noob
for jungling take Smite cus... i dont know ask stonewall008
for laning Cleanse for all the stuns slows roots....
UPDATE maybe [surge] is a possible Summoner Skill as well. I haven't try it but some bonus AS isnt too bad for him.

also possible:
Flash - like a noob
Exhaust - better gank early
Teleport - for laning yi
Heal - better towerdiving

rush Youmuu's Ghostblade asap
kill everything
farm, farm, farm but dont overfarm!
BE A PRO
and remember: YOU DONT KS, YOU ONLY INSURE THE KILL!

some examples:
mhh.. kay no more screenshots.. i will add more if i play him again

all honor goes to me. i am awsum. dont blame my english, im german and german can not speak anglas! share my awesome build. blabla~
nyancat lyrics:
nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan nyan...

Wup Wup~.

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