Hi, this is my recommended build on Master Yi,I picked him up recently because I wanted to try out what a brain dead champion felt like to play. My conclusion was that although Yi seems simple, he is actually pretty difficult to play, because his straightforward kit makes him very predictable, and closes many outplay options, so you have to rely on basic gameplay skills and decision making to play him well. In fact, you can say that to play Yi well, you must rely ENTIRELY on your decison making skills. These don't just include when to enter a teamfight, they also encompass objective control, when and how to splitpush, and itemization and runes. Yi, like many splitpush type champions, is about snowballing ANY LEAD YOUR TEAM HAS in order to win. That means you have to avoid messing up, whether by feeding or buying the wrong items. I've provided my item choices here as reference for people who might want to learn the champion more thoroughly, because although Yi seems easy to play, everyone's had those games where they just didn't make an impact, and want to know how or why they messed up.

Yi has simple abilities, you don't need to learn much about them. Just get used to them and learn to take advantage of auto-attack timers. You can use Q to cancel your passive double strike, auto>W>auto for a free auto attack, or actiavte E just before a Double Strike to maximize your damage. Use Q as a positioning tool, don't only use it for damage, Yi deals more damage with his autos anyway.

I've only listed the really difficult or annoying jungle matchups for Master Yi, everything else is not really important. Yi can deal pretty easily with most other junglers besides these 5, whether through dueling or vision or counter jungling. Udyr isn't really a threat as of the moment in S7, so I didn't mention him, Shyvana is not hard to fight as long as you don't fight her head on early, and Rammus is actually pretty easy if you buy both BORK and Merc Scimitar as well as Merc Treads. With enough damage, any champion that taunts you is looking for suicide.

I always start at my Red Buff, the passive heal and true damage burn helps your first clear a lot. Lately I've been going Red>Raptors>Wolves for the fastest level 3 you can get on any jungler. Trick to doing Raptors is simple, wack four of the small Raptors before Alpha Striking , then turn on Wuju Style and clear the small raptors before finishing the big one. Same deal with wolves, wack the small ones twice each and Alpha to kill them. I like to time my wolf camp so that the moment I kill the last wolf(the big one), I level up W and activate it to not waste time. The moment it finishes, go do scuttle with your remaining Red Buff and E true damage. Do Gromp>Blue afterwards, or just Blue if you are low on health. Back, start from Krugs, and do a full clear. Back one more time, clear around 2 camps, and you'll hit 6. This is the safest clear I can think of, the fast LV3 method gives you a lot of safety and opens up early gank potential. Also, you can actually avoid smiting with the first clear I mentioned and still be really healthy because of W heal at wolves and Scuttle. Important tip for Yi though, and any jungler you play: don't hesitate to drop any camp you are doing to go help a laner in trouble. Yi might have a weak early, but that is only considering how squishy he is and how some junglers have way too much burst compared with him. You still deal a lot of damage, so if you go and help, you might get an assist or a kill, maybe even two kills if you are lucky. Also, once you get Bloodrazor, look for opportunities to solo Dragon every chance you get, Yi takes objectives very easily. Same with Rift Herald, the new Rift Herld deals almost no damage and is ridiculously easy to kill, just keep wacking it from behind, it turns very slowly.

Yi is a squishy champion even when he builds tanky, so even if you think of yourself as a fighter, you are not. You are an assassin with more health. In team-fights, look to engage once everyone important on the enemy team has committed to something, then pick a squishy target and go in. A squishy target, mind you, not the highest priority target. They aren't always the same person, and you need to kill the squishy first to extend your Highlander enough to make an impact on the fight, and to get resets on your skills. Squishies first, then the priority target. Outside of team-fights, don't push a lane together with your team. Let them push together, you go push a side lane solo. That way you get more gold and EXP, and you will actually be useful. Yi is terrible at sieges, he can't hit minions or turrets at all because the enemy team will wreck his face. Tell your team to 4 man push instead, you go split-push, if the enemy team doesn't come, hurrah you get a turret or two, if they come, hurrah your team gets a turret or two, it's a win/win situation. If you notice that the enemy team is on their way to you, retreat immediately and group with your team to either finish their push or run for an objective like Baron. Or you could stick around and hide to see if they leave and go siege again, then continue pushing. If they only send one person to deal with you, congratulations. You will get a turret AND a kill in most situations.

You might be Master Yi, but you are still the jungler. And as the jungler, what is your role on the team? Map control. Ganks, objectives, etc; these are all important. But they are still nothing without warding. Vision is the most powerful tool you can utilize in League, don't be a fool and skimp on wards. Remember, when you spot the enemy jungler with a ward, you not only know where they are, you know where they aren't as well as where are likely to be or have been. This gives you a safe chance to take things from the enemy team. Camps, Dragons, lives; all because of a tiny ward that you planted in the enemy jungle. Buy control wards, and lots of them; if you don't want to buy a Sweeper, buy multiple control wards, plant them repeatedly in different places to clear out enemy vision in your jungle. Use your own wards wisely, never plant then in your own jungle, plant them in the enemy jungle's minor camps. Why? Because buffs take too long to spawn and are relatively quick to do, and because it's a lot harder to predict where they plan to go afterwards. Raptor camp is the safest camp to ward, with Krugs being second easiest. I never ward Gromp though, it's a lot better to ward Wolves, because everyone goes Wolves into Gromp, but not everyone goes Krugs into Raptors or Raptors into Krugs. If you want to take an objective, always make sure you have a control ward to check if the enemy has vison there. In any game, knowledge is power, and vision is the most consistent form of knowledge you can get. Think of it not as security, which is the passive perception of what vision does in League, but as intelligence gathering. You are spying on the enemy, gathering important intel for yourself and your team. How is that boring or not fun to do?