Jax is a very overpowered champion. He can't really get killed in 1v1, if you play him good and follow this guide you will be able to win some 1v2 fights or even a 1v3 fight. His leap makes you able to chase and flee. The stun is awesome in 1v1 or when trying to flee from one or more enemies.

Many Jax builds focus on ad but if you look at your damage after a match with Jax you will see that you deal ca three times magic damage than your physical damage. Attack damage is still very good because it boosts most of your abilities too. So as conclusion you will need both AD and AP but mostly AP.

Pros

• Awesome 1v1.
• Leap for killing of enemies, flee or just for the damage.
• Gets extra health for each bonus attack damage and ability power.
• Passive ulti is good for killing creepwaves.

Cons

• You are often focused.
• I can't really think of anything more :P

Mark
Greater Mark of Insight
You deal mostly magic damage so this will make you deal more damage, especially to tanks.


Seal
Greater Seal of Evasion
You're Jax, isn't that obvious?


Glyph
Greater Glyph of Force
Ability power, these are better than Greater Glyph of Ability Power after level 6. You will get that level very fast on dominion so Greater Glyph of Scaling Ability Power are the better.

Greater Glyph of Potency
Better than Greater Glyph of Scaling Ability Power until level 6.


Quintessence
Greater Quintessence of Potency
Gives you ca 5 times as much AP as a Greater Glyph of Ability Power so it will increase your AP a lot.

Greater Quintessence of Swiftness
Extra movement speed for chasing or fleeing.

Greater Quintessence of Fortitude
Extra Health is never bad.

Greater Quintessence of Evasion
This gives you only 2 times as much as a Greater Seal of Evasion would give you so I would rather recommend something above.

Many Jax builds go for the 21/9/0 build but I would rather take a 9/21/0 build because the offensive tree increases your attack speed or critical damage which isn't good for an AP Jax. Defense is always good and will help you to stay alive and get so many kills as possible before you have to go back and heal.

Core items

Ninja Tabi
12% dodge, obvious choice.
If you meet many AD champions you can even pick 2 of these, the movement speed won't stack but the dodge and armor will.



Awesome item, it stacks with your ulti and increases both attack speed for 1v1 battles and ability power.


Hextech Gunblade
Lifesteal + Spellvamp + attackdamage + ability power and an active that can deal damage and slow, awesome item for all situations.


Rabadon's Deathcap
Boosts your ability power which make you able to deal half of some of your enemies health in just one Leap Strike + Empower.

Other good items

Morello's Evil Tome
Ability power and 20 cooldown reduction which will make you able to spam your abilities more.


Rylai's Crystal Scepter
Great 80 ability power and some health for survivability and the slow is awesome for chasing.


Moonflair Spellblade
If you are having problems with slows, stuns etc.. also gives some extra AP.


Lich Bane
Ability power and movement speed. Also gives great damage after you performs an ability.


Priscilla's Blessing
Capture rate and a small sprint, good if you are capturing a lot.


Quicksilver Sash
Very underrated item. This item will save your life many times against enemies that have strong debuffs. Like Mordekaiser's Children of the Grave for example.



Also remember that items are very situational, sometimes you will have to buy other items than those I wrote here.

Always begin with one skill point on each ability. You need them all.
Max Leap Strike first because it will reduce the cooldown which make you able to chase, flee better and also deal more damage.
Max Empower after, it increases your damage for nearly no mana cost at all.
Max Counter Strike last. It gives you more dodge chance and make you deal more damage if you performs many dodges. It have less CD than your other spells but you also have to make a dodge so you can't really use it as often anyway. The stun won't stun longer if you but more points in this skill and that's why I take it last.

The skill sequence is very situational.
if you have to play more defensively for example, you have to take some points in Counter Strike.

Remember that you can use the Leap Strike on friendly creeps and champions so if you are fleeing leap to a creep on the way or if you're in the jungle, tell your team mates to come closer so you can leap to them and save you.

When chasing, don't always save on the Leap Strike to the enemy, sometimes it's better to use it on a creep or other champion just to get closer and then 5 seconds later use it on him.

If you are running away from some enemies and then another one comes right in front of you to surround you then you can just leap on him and then flash away and you will survive. this technique has saved me many times.

Flash
Awesome for chase or to flee a lost battle.


Exhaust
Perfect for 1v1 battles, chasing or fleeing or saving a dying team mate.


Ghost
Good for chasing and fleeing and also to move quickly across the map to save someone, take a kill, defend or conquer a capture point. You have to at least pick one of this or the flash spell.


Garrison
Great for defending a point or capturing one. Remember to put a mastery point in the Reinforce mastery.


Ignite
Great to finish that fleeing enemy off or to reduce healing from someone with great lifesteal or spellvamp.


Heal
This have saved my life many times and also my team mates but it's better if someone else in the team picks it.

Jax is a very fun champion to play as and is the first one I ever bought. I hope this guide will help you on the battlefield.



"Imagine me with a real weapon" -Jax