Master Yi can be played many different ways but I think that many people underestimate the meditate skill of master yi and how effective it is. its a great champ but its even better if you know what your doing.

Benefits



+Great for first blood.
+Great pusher/tower/farmer destroyer.
+Pretty easy to learn overall.
+Great escape/chase mechanism.
+CD resets when you get a kill/assist(if Highlander active at that moment).

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Drawbacks



-Vulnerable to disables like blind, stun.
-Low HP.
-targetted in team fights.

Greater Mark of Attack Speed:These runes are there to give you 15,3% extra attack speed which is a great start of the game.

Greater Seal of Armor, Greater Glyph of Scaling Magic Resist:Thanks to these 2 runes you can have a lot of resistance against your enemy

greater quintessence of Desolation: thanks to these you have 10 more armor penetration and hit away like 1/3 of there armor and do a lot more damage

Well here comes the part of Meditate first you go into the fight with your Alpha Strike dealing 300+ damage to 4 enemies you can activate Wuju Style and deal as mush damage as you can and then when they target you you use your Meditate you get 700+ health and a lot of armor and magic resistance. if you are still not going to survive use Highlander to escape or finish the person(people).


Jump on the person with your Alpha Strike en using Wuju Style to attack him run after him with Highlander try to finish him or use Meditate and run away.