If you read this guide you've already chosen to play Irelia, so you said yes when you could have said no!

To learn Irelia isn't easy at all and you're going to need some time for sure. First of all I want to say that you can play Irelia many different ways - this build is just one among thousands. In a short form to explain this build, it's an offtank AD carry that hits hard and survives a lot, this means NOT that you should initiate a fight!
However have fun by reading this guide and I hope you learn some things about Irelia.

PS: I'm sorry for my english - it's not my native language!

EARLY GAME

First of all it's important which lane you take. Solo lanes are always good with Irelia, if you aren't able to solo you need someone who doesn't need farm on your lane - otherwise you will destroy his game. You also need to know that Irelia needs farm, so early on you should just farm as much as you can without dying. You won't be able to get kills before you got some items anyway, except your enemies do not play good at all. So early on just try to get a lot of creepkills and experience that's why it's really important to get items that helps you to stay in lane. Use Bladesurge to get creepkills and Hiten Style to heal yourself. You shouldn't use Equilibrium Strike to farm, you can harass from time to time with the following skill order:

Hiten Style >> Bladesurge >> Equilibrium Strike >> autohits

Don't harass if you might die or get more damage than the enemy and try to stun with Equilibrium Strike. If you get pushed to tower and there aren't any teammates nearby you can even use Transcendent Blades to defend the tower, heal yourself and get some creepkills.

MIDGAME

After you got some farm you can start killing enemies. Try to get a single enemy that isn't close to a tower and go for him. Use Hiten Style+ Bladesurge to jump on him, Equilibrium Strike to stun/slow, autohits to deal a bunchload of damage with each hit and, if you're able, use Transcendent Blades to deal some extra damage and heal yourself. You can also use Exhaust instead of Equilibrium Strike to slow him and if you get below the enemy's HP you can stun him.

In fights 1vs1, never use Equilibrium Strike before you can stun him for sure or to chase properly (if he's just running), it's really important to keep that in mind. Let him take you down a bit while you're hitting him as well and before you are close to death, use Equilibrium Strike and kill the enemy with Hiten Style and Bladesurge. If you know you can't kill him, just run after you've stunned him.

As well it's really helpful to get red buff in this time, but make sure you won't die after you got it. It's not wrong to help your teammates to get bluebuff, Irelia actually doesn't need it so let another one take it.

LATEGAME

From now on you should be able to take almost every enemy down in a 1vs1 fight. Make sure you never attack more than a single enemy - Keep in mind, you're not the tank. After a teamfight has began pick the enemy damage dealer and kill him before he kills your team, if they have really nice supporter with shield and/or heal, it's not wrong to get this one down first.
You should always activate Transcendent Blades in teamfights and use them to hit as many enemy champs as you can to deal more AoE damage, heal yourself and use Hiten Style as many times as you're able.

Usually Flash is almost a must have, so it's kind of stupid if you don't get it. If you really dislike Flash you might take Ghost instead (if you do, don't forget to take Haste instead of one point in Good Hands ). One of them is needed to escape or chase well.

Flash
Better escape than Ghost and much more worth since you'll get Trinity Force for enough movement speed.

Ghost
Actually a nice summoner spell to chase and run, but actually worse than Flash at least for Irelia.



For the second summoner spell you should choose between those:

Teleport
I think it's best summoner spell for solo top lane, if you aren't soloing a lane don't take this. Otherwise it's the best way to farm gold and experience. Ask your teammates to put wards close to their lane and you will be able to gank with this for some sure kills!

Exhaust
This summoner spell is nice to use as offense spell to lower enemies armor and slow or defense to slow the enemy and run. If you are laning with support (for example), take this spell since he'll give you an advantage.

Cleanse
This one is actually pretty nice, but I don't like it with Irelia since you got Ionian Fervor and Mercury's Treads which grant you a very similar effect.

Ignite
Can be useful against enemies that heal themself a lot, but actually it's good in early game and gets only worse in lategame. Since you play passive early on, it's more or less useless for Irelia.


I've chosen Flash and Teleport because they're useful to farm as hell in early game and in lategame they'll give you good map control.
The rest of the summoner spells aren't worth to be explained, so I haven't explained each of them.

Marks and Quintessences

For this build I take Desolation ones for both of them, means you will have 25 armor penetration since the beginning of the game only with runes. These runes are important for this build and shouldn't be changed.
Greater mark of desolation
Greater quintessence of desolation
(If you really have problems to stay in lane for long enough,
you can also get greater quintessence of vigor)


Seals

Greater Seal of Armor => Nice to play solo lane against harassment by enemy's autohits.
Greater seal of defense => Your role as an offtank in lategame gets more important.
Greater Seal of Evasion => Same as armor and armor per lvl, but weaker I'd say and kind of useless without Nimbleness.
Greater Seal of Attack Speed => Might be useful if you want to deal more damage and survive a bit less, but I wouldn't suggest these.


Glyphes

Greater Glyph of Magic Resist => Good against early game harassment by mages.
Greater Glyph of Scaling Magic Resist => Your role as an offtank in lategame gets more important.
Greater Glyph of Cooldown Reduction => Kind of useful for Irelia to play her more offensive.
Greater Glyph of Attack Speed => Only if you go Madreds in the end or something that can use the attackspeed.

LEARNING

R > Q > W > E
Transcendent Blades >> Hiten Style >> Bladesurge >> Equilibrium Strike

But I prefer to have at least skilled EACH of them once before skill another one twice (except for Transcendent Blades). This order prevails only if you can enough last hits early on already, otherwise you should favor Bladesurge over Hiten Style for some last hits. As I said I level Hiten Style to stay in lane for as long as I can while Bladesurge is important last hit creeps and get my farm while one second stun is usually enough to change the whole situation in a fight.


USING

You should always initiate with Hiten Style+ Bladesurge, except your enemy already attacked you. If you want to flee, always use Equilibrium Strike first to stun or at least slow the enemy. If you want to fight, only use Equilibrium Strike to stun, never waste an Equilibrium Strike for a slow in a fight you don't want to run away or chase the enemy down. Activate Hiten Style always before Bladesurge to deal additional true damage with it. If you can't get the enemy down because he is just faster, use Transcendent Blades to deal damage and heal yourself, don't forget that you can still attack and use other skills while Transcendent Blades is activated.

If you want to chase an enemy you can also use Bladesurge on a creep (better ranged one) and use it right after again on the enemy champ. Keep in mind, the creep must die that you can use it righta after again!

Since you will buy many defense items you won't need many points in the defence tree. So you can choose between 21-0-9 or 9-0-21. Actually both are playable, but with Philosopher's Stone you won't lack of mana at all what means 9-0-21 would be a waste. In addition the armor penetration from the offense tree are very nice as well. Instead of Utility Mastery you might want to get Greed ; since you don't need buffs in fact you can pick what you desire.

There are some combinations that work well with Irelia like 13-6-11 where you'll get some defense from Resistance and Hardiness . But in the end I think it's best to max one tree.

common questions:
Why did you put three points in Good Hands and only a single into Perseverence ?
=> If you calculated the outcome of Perseverence, you wouldn't ask.

Why didn't you put points in Alacrity ?
=> Again the same, calculate it and you will see, it's really useless for kind of all champs - I'd say.

As I said in the beginning, the item build is useful if you want to play as offtank and in the same time as AD carry. First of all you start with a Regrowth Pendant and a single Health Potion. The reason for these items is that you must stay in lane as long as you can because the experience are important to you. In addition you should get some creep kills what means you'll get hit a lot as a melee. If you lack of HP in the beginning Doran's Shield might help you instead of Regrowth Pendant.

The first time you teleport back, you should finish your Philosopher's Stone and start or even buy entire Mercury's Treads as well. If you can't afford the item, try to buy Boots at least and take some Health Potion with you. The Philosopher's Stone will help you farm and stay on lane without lacking of HP or mana while Mercury's Treads improves your passive ability Ionian Fervor.
The next item you will get is your core item - Trinity Force. It's probably the most important one. Just buy the part first you need most, Phage is always nice for the HP. If you need more burst damage get Sheen and if you lack of attackspeed or movement speed get Zeal. It really depends on the situation!

After you've got Trinity Force it should be around 20 or 25mins. Before you get Black Cleaver you should get either Chain Vest or Negatron Cloak to get some more survivabilty - what you get depends on the enemy team. Instead of them you could also get a Wit's End or Spirit Visage. After that you can start Black Cleaver. This items gives you usually enough attackspeed, attackdamage and armor penetration for the rest of the game. Instead of Black Cleaver you can also get the entire Banshee's Veil first if your enemy team has got a lot of magic burst damage and/or CC and your Tenacity or HP aren't enough. After all these items I'd go for Guardian Angel, because you're probably get focused and die too early in teamfights.

Now your item build looks like:



After you've got all these items, it really depends on the opposing team what you get next.
As soon as you've decided what you will get, you can sell your Philosopher's Stone and get the item.


Some options for last items would be:

Spirit Visage
It's actually a nice item, if you want to get this item, get it right after Trinity Force and before Black Cleaver.
( Chain Vest/ Negatron Cloak not needed than)

Shurelya's Battlesong
If your enemy team is stacking movement speed and your team isn't able to chase properly this might help.

Atma's Impaler
It's a nice item against AD champs that gives you some more damage, the only thing is that you won't have that much HP with this build so its not that good.

Force of Nature
This item suits Irelia really well, since the defense makes you more tanky and the movement speed and health reg are a nice addition. This item is a good alternative for Banshee's Veil.

Frozen Mallet
If you cant chase your enemies well enough and you aren't able to get/keep red buff.

Hexdrinker
Quite nice but only get it if you're lacking of farm and enemies nuke you really hard or Requiem.

Last Whisper
Your enemies stacked so much armor and aren't dealing much damage.

Madred's Bloodrazor
Your team lacks of magic damage and enemies do NOT have much magic resistence. (Good alternative to Black Cleaver with an additional armor boost.)

Randuin's Omen
You need some more armor and your team needs the slow. If you go for this get an early Heart of Gold.

Sunfire Aegis
You need much more survivability against AD and your team lacks of AoE damage.

Wit's End
You're lacking of magic resistence.

Youmuu's Ghostblade
You could need some more armor penetration and attackspeed.

Bloodthirster
You deal a lot of damage but don't survive long enough.

Hextech Gunblade
You deal a lot of damage but don't survive long enough and might need an additional slow.

Sword of the Divine
Nice way to counter Jax or a team full of dodging guys.

Zeke's Harbinger
Also really nice to get some HP reg with lifesteal, attackspeed and armor penetration for sure.