Hi I'm Sashi5678 and i want to share my build with you with a little help from my friend Luke9700 I recommend this build for 3V3 and 5V5 this is my first guide on mobafire and feel free to ask a question.

Marks (red) - I recommend 9x Greater Mark of Strength, that means 9 x 0,95 AD (total 8,55AD), but thanks to Jax passive, the AD give him another 26 HP

Seals (yellow) - dodge runes 9x Greater Seal of Evasion, no discusion.

Glyphs (blue) - three options here:
1) 9x Greater Glyph of Celerity, that means 9 x 0,05% CDR ( 8,62% on lvl 18 )
2) 9x Greater Glyph of Potency, that means 9 x 0,99 AP (total 8,91 AP) and thanks to Jax passive additional 17 HP
3) 9x Greater Glyph of Force, stacking AP runes are viable option. They give more AP than flat AP since lvl 6 and that is right the time when you get your Ulti. If you decide to choose them, I suggest to buy some CDR item (check in Item section)

So far best quintessences are for flat AP, that means 3 x Greater Quintessence of Potency ( 3 x 4,95 AP = 14,85 AP = 29,7 HP)

I will start this chapter with look at skills Jax have.

Equipment Mastery is Jax passive. Simply said the more AD and AP you buy, the more HP you receive. Every 1 point of AD means 3 HP and every 1 point of AP means 2 HP. So the idea while playing Jax is to build items that provide AD and AP and as nice bonus you get HP. Pretty cool passive, huh?

Leap Strike is Jax Q. Its a "close gap spell" that deals nice damage combined with Empower. It get 100% bonus damage from your AD. The cool is that you can jump (ofc to an enemy) to any friendly units! That means: your ally, your minions, wards, Teemo mushrooms/satelites, little Shacos (box) etc. This greatly improves your movement over battlefield. You always want to jump with active Empower (for harras).

Empower is Jax W. It charges your lamppost with energy that is released into an enemy with auto-attack, but even with Leap Strike. After you push your W button you have 7 seconds to attack, or its wasted. Another cool thing is, that it resets your auto-attack timer.

Counter Strike is Jax E. This is (IMHO) one of the coolest spell not even on Jax but at all champions. Why is it so special? It has two effects. Passive: your dodge chance is increased by 10/12/14/16/18%. Cool! With runes and boots...34% dodge (Capt. Obvious says: you dodge every third attack) And there comes the Active: After dodging an attack you can stun surrouding enemies for 1 second and deal magic damage to them. (Capt. Obvious is very excited now). You can stun max 7 seconds after dodge (tips in following chapters). This is your secret weapon allowing you to 1 vs 2, eventualy 1 vs 3. It is possible, trust me, I survived that situation several times and scored triple kill!

Relentless Assault is Jax ulti. Passive effect is mad stacking thing (I miss proper word for this) and makes Jax so dangerous. Its easy, with every additinal attack your attack speed is increased. Thats the point why you want and can kill minions wave this (-) fast. (Capt. Obvious says: REALLY FAST). But thats not all! Every third attack, and it doesnt matter if its dealt to same target or another, deals bonus magic damage (140/170/210). It makes some pfth sound. The only disadvantage is that you have to land those attacks fast after the previous (2,5s) and that can be sometimes a problem. The Active is a survivability stuff. If you activate it you get bonus Magic resists. It depends of Ulti lvl and your dodge. (Capt. Obvious says: more dodge, more MR, got it?) Relentless Assault greatly synergyses with Guinsoo's Rageblade.

Hextech Gunblade
Attack damage = 40 (nerfed from 60)
Ability power = 70 (nerfed from 75)
Lifesteal = 15% (nerfed from 20%)
Spell wamp = 20% (nerfed from 25%)
Unique active = Deals 300 magic damage a slows the target champion by 50% for 3 secs, range 700
Cooldown = 60 secs
Price = 3625 gold (same after nerf)

Guinsoo's Rageblade
Attack damage = 35
Ability power = 45
Lifesteal = 0%
Spell wamp = 0%
Unique passive = On attack or spell cast, increases your Attack speed by 4% and Ability power by 6, 8 stack max, stacks last 5 seconds
Cooldown = none
Price = 2235 gold

And the happy end. Jax is great DPS, he can challenge every another DPS in game due to high dodge (34% at lvl 18). He is pretty fast and with high HP, so he can sustaine very long time in team fight.

Thanks for reading I hope this helped you and I hope to get more thumbs up then thumbs down. GL :-)

P.S Luke9700 has a couple of builds so far he has one for Xin Zhao and one for Twitch i hope you can check out some of his builds too.