Health: 428 (+85 pr. lvl)
Attack: damage 55.8 (+3.2 pr. lvl)
Health: regen. 6.25 (+0.7 pr lvl)
Attack: speed 0.651 (+3% pr. lvl)
Energy: 200 (Manaless)
Armor: 16 (+3.7 pr. lvl)
Energy regen: 50 Magic res. 30 (+1.25 pr. lvl)
Range: 125 Movement speed: 325

Flurry (Passive): After Lee Sin uses an ability, his next 2 autoattacks within 3 seconds gain 40% attack speed and return 15 energy each.

Sonic Wave: Lee Sin shoots a wave of sound in a line, dealing physical damage to the first enemy it encounters and revealing it for 3 seconds. If Sonic Wave hits, Lee Sin may cast Resonating Strike within the next 3 seconds.
Cost: 50 energy
Range: 975
Cooldown: 11 / 10 / 9 / 8 / 7 seconds
Physical Damage: 50 / 80 / 110 / 140 / 170 (+0.9 per bonus attack damage)


Resonating Strike: Lee Sin dashes to the enemy revealed by Sonic Wave, dealing a base amount of damage plus 8% of their missing health as physical damage. Monsters take a maximum of 400 damage.
Cost: 30 energy
Range: 1100
Base Physical Damage: 50 / 80 / 110 / 140 / 170 (+8% enemies missing hp) (+0.9 per bonus attack damage)

Safeguard / Iron Will: Lee Sin shields himself, or dashes towards a target ally unit, shielding them both from damage for the next 5 seconds. After using Safeguard, Lee Sin can cast Iron Will within the next 3 seconds.
Cost: 50 energy
Cooldown: 9 seconds
Range: 700
Shield Strength: 40 / 80 / 120 / 160 / 200 (+0.8 per ability power)

Iron Will: For the next 5 seconds, Lee Sin gains bonus lifesteal, spell vamp, and armor.
Cost: 30 energy
Spell Vamp & Lifesteal Bonus: 5 / 9 / 13 / 17 / 21%
Armor Bonus: 10 / 15 / 20 / 25 / 30


Tempest: Lee Sin smashes the ground dealing magic damage to all nearby enemies and revealing them for 4 seconds. If Tempest hits an enemy, Lee Sin can cast Cripple within the next 3 seconds.
Cost: 50 energy
Cooldown: 10 seconds
Radius of AoE: 350
Magic Damage: 60 / 95 / 130 / 165 / 200 (+1.0 per bonus attack damage)

Cripple: Lee Sin cripples all enemies revealed by Tempest reducing their movement and attack speed. The movement and attack speed recover over 4 seconds.
Range: 500
Cost: 30 energy
Initial Slow: 30 / 37.5 / 45 / 52.5 / 60%


Dragon's Rage (Ultimate): Lee Sin performs a powerful roundhouse kick, dealing physical damage to the target and knocking them back. Enemies the target collides with take the same amount of physical damage and are briefly knocked into the air.
Cost: No cost
Range: 375
Knockback distance: 1,200 (estimate)

Lee Sin's Flurry adds 40% attack speed to the two basic attacks that immediately follow, each of which also refund 15 energy. In order to maximize this buff's effects, stagger (space out) your abilities a few seconds apart while staying in combat.
Lee Sin can quickly fire off his abilities and their secondary effects before they go on cooldown. This gives him a lot of burst-type damage, but will quickly deplete his energy. As it is with most champions, the key to becoming a skilled Lee Sin player is to adapt your strategy to maximize his passive ability. Stay in melee range and wait a couple of seconds before using your ability.
The combo of Sonic Wave and Resonating Strike is very useful for hit-and-run exchanges. You can use Sonic Wave at range and then close the distance with Resonating Strike, initiating melee combat. Or, if you are already in melee combat, you can use Sonic Wave as you fake to retreat, hit Resonating Strike, coming back for more.
Resonating Strike can be great way to close in on your opponents. You can use Resonating Strike when you are slowed, go through some walls, and chase enemies through slowing AoEs like Trundle's Pillar of Filth.
Be careful when immediately using Resonating Strike after Sonic Wave. You may end up charging right into a turret, an enemy champion in the brush, or even a 5v1 situation if you're not careful.
One of the most effective methods of harrassing with Lee Sin is to use Resonating Strike to attack an enemy and then immediately retreat with Safeguard. This can be a powerful move early on in the laning phase. You can begin using this combo as early as Level 2 and often the opposing champion(s) have limited means of retaliation.
Safeguard is essential to have "leveled up" when you're facing off against an Attack Damage Champion.
Sonic Wave & Resonating Strike is a powerful combo and using Safeguard to rush back to the safety of your allies makes Lee Sin an awesome harasser. Setting Safeguard to smartcast might be just enough to give you that edge you need to be quick with this strategy of dashing in and then out.
Safeguard has a primary defensive use but it can be effective in an offensive context as well. If an enemy Champion is out of line-of-sight for the Sonic Wave skillshot, but is in melee range of an allied minion or Champion, use Safeguard to jump right in.
If you are jungling, always remember to use Iron Will before using Smite and/or Sonic Wave, as it restores Health through Spell Vamp.
Safeguard cannot be cast while snared, even if Lee Sin targets himself. If you are engaging an enemy that has a snare, either ask for help or cast the ability pre-emptively to still be able to tank the snare's damage.
Using Dragon's Rage on the enemy tank at the beginning of a teamfight can disrupt the enemy team's positioning. Not only will Dragon's Rage knock the tank back, but it will also knock up the champions hiding behind him.
Similarly, you can use Resonating Strike to get to the back lines and Dragon's Rage their carry to your team, temporarily disabling their tank if he gets hit by his own carry. Follow it up with a Safeguard to get back to your team.
During a team engagement, try to use Dragon's Rage on a carry who overextends to isolate him/her from the team and pick up an easy kill.
Be careful about using Dragon's Rage as a finisher, as one incorrect calculation may lead to the target escaping instead.
You also have to make sure to aim Dragon's Rage correctly, depending on where you are, as this can prove to be crucial mistake in team fights. For example: kicking an enemy champion out of range of a friendly Amumu's Curse of the Sad Mummy.

Due to scaling well with attack damage, but requiring a fair amount of survivability due to how close he must get to enemies while he fights, getting items like Wriggle's Lantern Lantern and Hexdrinker early can have noticeable results.
If played in lane, Atma's Impaler will be more beneficial than Wriggle's Lantern, especially if building more towards the tanky side of tanky DPS.
Atma's Impaler is a generally great item for Lee Sin; consider complementing it with a Frozen Mallet and/or Warmog's Armor.
Randuin's Omen is a viable item for Lee Sin, complementing his ability to slow movement and attack speed.
Trinity Force is a fantastic item for Lee Sin. Since he has 7 skills, he can constantly proc the effects of Sheen. Coupled with his passive, he is very likely to proc the Phage effect giving him excellent DPS and chasing. However, given his strong attack damage scaling and natural squishiness, it is best to get Trinity Force late, instead going for attack damage/durability items such as Wriggle's Lantern, Hexdrinker, Phage, or a few Doran's Blade's.
Trinity Force will also provide some ability power to beef up the shield from Safeguard without sacrificing an item spot purely on AP, in addition to its plethora of beneficial effects and stats.
Lee Sin can drop a tower fast if he has Trinity Force because his low CD abilities do not require targets to cast, allowing him proc the bonus damage every 2 seconds.
With Youmuu's Ghostblade a midgame Lee Sin can singlehandedly push a turret. Stagger your abilities to trigger Flurry while activating the Youmuu's Ghostblade active.
Since Lee Sin does not use mana and scales well with attack damage, it can often be better to build the much cheaper Hexdrinker rather than the more expensive, but more popular Banshee's Veil (which Lee Sin wouldn't be able to use the mana portion of anyway).
Building Lee Sin tanky is important because to use his ult properly he needs to be able to survive being in the middle of the fight.
When playing jungle Lee Sin, you can use Wriggle's Lantern to place free wards for not only vision and map control, but also for synergy with Safeguard. This allows you to jump over walls to gank/escape enemies.
Getting tanky with a Frozen Mallet or Warmog's Armor will allow you survive longer and give you more attack damage if you get Atma's Impaler.
Getting Bloodthirster on Lee Sin will have profound effects with his damage output and regeneration.
Attack speed is a non-optimal build path on Lee Sin, as most of his damage comes from AD-scaling abilities, and his innate Flurry grants him natural AS.

Most of his spells deal physical damage. Investing in armor items will mitigate his damage output.
Resonating Strike will deal a lot of damage when you are low on health. Try to dodge his Sonic Wave so he can't use Resonating Strike to finish you.
Cripple will only slow you if he hits you with Tempest. Make sure you stay away from the ability's AoE in order to avoid the slow.
Instead of battling him in minion wave, try to fight him when he is alone so he can't make the full use of the dash from his Safeguard.
Keep in mind that he can still cast Safeguard on himself to gain its shield and regeneration from Iron Will.
When playing as a stealth champion, wait until Lee Sin uses Sonic Wave and Tempest so you won't get revealed from your stealth.
Lee Sin's Dragon's Rage will knock you back to a set distance. If he targets you, it's better to run away in the direction he kicked you rather than running through Lee Sin to escape.
Be extremely careful not to use Flash to escape while affected by Sonic Wave, as he can stick up to you with Resonating Strike]. [[Lee Sin can activate Resonating Strike to jump to you, from a long distance away, although there is a range to his ablility.
Save Flash until Sonic Wave wears off or Lee Sin has already used Resonating Strike.
Keep in mind that Lee Sin's abilities have high Energy costs when engaging him. He will be vulnerable and unable to take much action if he is Energy-starved.
Keep your team spread to minimize the effect of his Dragon's Rage.

Viable Choices

- Exhaust: Good if you are going to top, so you can secure a 1v1.
Also good if ganking to get a high movement speed slow on the target.
- Ignite: My favourite spell for finishing someone off, and reducing healing regeneration, like Dr. Mundo or Swain which has crazy health regeneration with their ultimate.
- Teleport: Also a excellent choice if going top, if you die or recall, you can fast shop and then teleport.
- Heal: Good to pop out when you're dangerously low, and then use it and defeat your enemy.

Unviable Choices

- Clairvoyance: Support Lee Sin is not my type of sausages.
- Promote: I never chooce this, because you could have a better spell like Ignite, Exhaust or Flash
- Surge: No reason to take this, as only his Safeguard is scaling on ap, and Lee Sin doesn't need attack speed.

Pros

Good AD scaling.
Awesome tank.
High mobility
Good CC.

Cons

Hard to master.
Overused.
Often banned in rankeds.

When jungling always take Summoner spell Smite. Good to take and early boots and Wriggles.

Blue buff spawns at 1:55
Respawn cooldown: 5 minutes

Red buff spawns at 1:55
Respawn cooldown: 5 minutes

Dragon spawns at 2:30
Respawn cooldown: 6 minutes

Baron spawns at 15:00
Respawn cooldown: 7 minutes

Tips:
Give your AP carry blue as you dont use mana, and dont need cd.
Gank once before recalling. Remember to have one in E and one in Q when ganking.

At early game you should be focus on last-hitting and harrasing. If you can get about 120-140 minions on 15-20 minute mark, you should have some succes.
Last hit so good as you can, because you build is very expensive.

10/5/12:
Published guide.
8/6/12:
Fixed some words, that was spelled wrong.
Added Atma's Impaler to the cheat sheet.
15/8/12:
Changed all the cheat sheet, putted BBCoding in the guide
Reworked it
And wrote some things in the Build Usage section.

I wan't to say thanks to everyone who took a look at this guide, special thanks Jhoijhoi for her "How to make a guide" guide.

If you liked this guide, please vote up, if you didn't like please tell me what I can do better!
I would really appreciate constructive feedback :)

BYE!