Hey, this build is kinda good. But you need a total gold of 17160... Thats pretty much ! So its hard 2 get youknow.. And there are some cheapier other builds where you get your damage more quick.

Jax is a character that can get crazy attack speed along a high Damage, I'm not lacking on magic pen to do damage because the main way I'm dealing damage is physical and all I need is armor pen, and 45 armor pen is enough to allow you to easily kill any squishy, especially since your attacking at 1.562 attack speed and getting up to 2.302 in less than 3 seconds and applying that 45 armor pen in that time, at that point with lifesteal you're pretty much unstoppable, and with an AOE stun that stuns for a second, in that second you recover over 800 hit points with the kind of damage you put out, that's not even including that extra spell vamp from the ult passive, plus the masteries are key for magic pen, I get that 15% magic pen you wanted to see from, Archaic Knowledge(mastery) and I don't have to use my runes to do it.

"Archaic Knowledge is simple magic penetration , 15%!!! thats a lot and its helps your 3rd attack on target(ult), Empower (the ability you rely on), and Leap Strike all do more damage on a regular basis."
`` I said that in a section of the build, so instead of getting my spell pen from items its from the masteries

I know you like attack speed, but wouldn't armor pen or spell pen runes be more beneficial to Jax? With marks and masteries you can easily get around 22+ armor pen or 15+ magic pen. Since you aren't buying any items other than Black Cleaver with penetration, are you lacking on killing power? If not, why is that?

OMG THIS IS THE BEST BUILD I HAVE EVER SEEN!!!!!!!!!!! +1 :D

thx and btw sorry to all for spelling mistakes

great guide well explained +1