Hello, I'm Lord Barchy. Maye you have played with me, maybe not but it's not the point now.
English isn't my motherlenguage so I may have some tipping errors or vocabulary problems but I hope you will understand this guide.

I've made this guide based on my own game experience with this char and I have to say that following this build it's been pretty good, normal score for me with this build is something about 3x/x.

I think this is one of the best builds for Jax and hope you like it too.

Lets go!

I choosed those runes because early game they are very useful, mid gae they can serve you and late game they may be very useful too. If you dont like those CD glyphs you can change them for some Mana Regen, because even if you dont think so, Jax burns MP as a mage. Naturally his spells doesnt cost much mana but he doesnt have much natural mana neether, so some mana regen should be very useful early game.

Nothing to do with the masteries, exept if you want some personal changed bases on your play mode.

If you dont see it pretty clear on the iteams part, I will detail it now;

1°You have to start with the $350 Boots and 3 HP Potions.

2° As soon as possible, you may buy Ninja Tabi (Dodge Boots)

3°Buy one Vampiric Scepter.

4°Buy one Hextech Revolver.

5°Complete the Hextech Gunblade

-By this point you should be able to start farming enemys. But dont trust too much, you havent got your full power jet, dont go solo 3v1, wait a bit and hunt from the shadows the lamers (enemys who go on alone on the map).-

6°Following the same orden before (Vampiric Scepter, Hextech Revolver, Bilgewater Cutlass...etc) but another Hextech Gunblade

7° You will start making the Infinity edge. I recomend to start with the Cloack Of Agility cape (as its show on the item part)

8°Buy the B.F Sword and the Pickaxe. Complete the Ifinity Edge as soon as possible.

9°Buy another Hextech Gunblade

10°Buy the Phage

11° Complete the Trinity Force.

-Now you are ready to start killing all the enemys by yourself.-

If you do it everything ok, you should be like this:

-Crit change: Like 36%
-Crit atack damage: 8xx-900 (with chance to slow your enemy)
-Normal atack damage: 4xx
-Ability Power: 2xx
-Sleap Strike damage: 700-800
-Empowered damage: 5xx-6xx
-Counter Asault (Ulti) passive damage (one "empowered" hit every 3 consecutive normal hits): 300-4xx
-Life Steal: 60%
-Spell Vamp: 75%

PD: This build has one unique problem, you will be very eas target it the enemy stuns you. You can always get one Guardians Angel late-game instead of one of those Hextech Gunblade.
Because Jax passive you will have something about 3.xxx HP.

You should start with Leap Strike, because it hits depending on your AD (Atack Damage) and your AP (Ability Power).
Then you should grow up (in lvl 2) "Empowered", from now on it will be really easy to get some kills and farm enemys. You just have to low theire life with "Empowered + Leap Strike" then you use your "Exahust" and if you need it ignite. It's not hard :)
At lvl 3, you may lvl up Counter Strike, it gives you the stun you need for killing even more easy enemys. On this times, having the minions on your enemy side will be very useful (more minion hit, equals more dodge and dodge means stun, and stun means sure death).
You should lvl up as priority you ulty and empowered. Then Leap Strike and only at the end of the game when you dont have any other spell to lvl up, Counter Strike.

IF you want money (as everbody wants) you just have to kill minions and champs. From lvl 9 on (you should have the Vampiric Scepter and the Hextech Revolver) it should be very eas to kill enemys, minions and to jungle, most of times you may end more then 3/4 HP.

Your Exahust spell and Ignite will be very useful for farming enemys. Your critical hits will be brutal and the enemys will fall on your foot. Your spells will hit like beasts and nobody will stop you!

Here is one image of one of my latests match with Jax:
My best run with Jax was 37/4/10 in a 5v5 normal game at lvl 30.
----

This guide was made complete by me. I would like to thank my friend Pentagrama, who showed me this champ.
Hope the you liked the guide and it serves you a lot. Remember that this is my first guide, so dont be so mean with me :P

Any other info you may want me to add, feel free to ask for.