Jayce is a really cool, fun-to-play champion. This is more of a self-reference item build than anything, but you can try it if you like. I explain my choices below.

Marks: I chose Desolation because, as we all know, Armor is stupid because it makes it harder for us to deal with evil-doers. Pick up these for a small damage boost.

Seals: Since Jayce has little in the ways of defense early-game, extra armor is a good choice for survival.

Seals: Again, for the early-game, when you run out of mana. Jayce's abilities have low mana costs, so the extra ~100 mana you get from these goes a long way early on and later on, these will still make up a good portion of your mana pool. Once you do run out, just recover it using Lightning Field's passive.

Quintessences: Here's some bonues AD which scales, so you can hit a bit harder all throughout the game.


ALTERNATIVES: You may want to take Crit Chance runes, as they interact well with Infinity Edge and the Deadliness mastery. Flat defense runes are also a good choice, due to Jayce's early-game squishiness. If you're concerned about mana (particularily if you favor the Mercury Cannon over the hammer), pick up some mana regen runes.

Quite simple, really. You get bonus AD, some armor penetration, and a teeny bit of lifesteal. The defense masteries help you survive early on, when Jayce is especially vulnerable to damage.

Here's the fun part. Below are what purchases you'll make over the game:

- First: Boots + 3 Pots
Mobility is quite useful when you're going to be switching between ranged and melee constantly. The pots help your sustain.

- After: Doran's Blades/Phage
This depends on how much cash you have at this point. If you can stay in lane long enough or get enough early kills to get the gold required for Phage, good for you. If not, pick up a Doran's Blade (or two, if you need both of them) so you can stay alive while taking out the enemies creeps (and champions) with the extra AD, and save up to get Phage after.

- Then: Giant's Belt, Frozen Mallet
Ultimately, you want to get the Mallet, as it gives you a load of extra HP and a slow, which Jayce lacks. If you can't afford it yet, buy the Belt to build into it first.

- Vampiric Scepter
Now that you've got the Mallet, dying does not concern you as much, so get this to keep your health high over long periods of time in-lane. Once you have this, it becomes a useful strategy to go after jungle monsters to get back your mana using Lightning Field's passive, as you can lifesteal back any damage you take from them.

- Mercury's Treads
At this point, you'll probably be concerned about mages roaming around with their CC spells, along with other things like Ashe's Frost Shot. Jayce does not like slows, so pick up the Treads for their Tenacity buff.

Some time after this point, you may find it a good idea to sell of your Doran's Blades to free up room and gold. You shouldn't need them anymore, anyways.

- B. F. Sword/The Bloodthirster
Now, the BT is an expensive choice, so there's a good chance that you won't be able to buy it in one go without investing in a B. F. Sword first. You'll probably be able to get enough gold for that, though you may have to take down some jungle creeps for the last few coins. Once you've built the BT, however, you'll have tons of damage, some good lifesteal, and a stacking passive that you can build up very easily, as Jayce is the lord of CS.

- Infinity Edge
Focus on finishing this next. It's a standard part of any AD carry's kit, and a very strong choice due to the high damage it offers. It also pumps up your abilities, which is nice.

From here on, the build is much more flexible, and you should take whatever you need for the current game.

- Last Whisper
Very srong versus anyone with armor. This will give you a lot of damage late-game, and is practically a must-have against champs building up a lot of armor. If you're on an AP-heavy team, and the enemies have no Armor items, you may replace this with The Black Cleaver or something else.

- Guardian Angel
This helps your survivability by giving tons of armor and magic resist. Again, this should be replaced if there's a better choice - if you fear AP more than AD, you could take a Banshee's Veil, and if the enemies are building heavy armor/magic penetration, Warmog's Armor can be more effective.

- Elixers
Buying these with a full inventory causes them to be drunk automatically. Your build is already finished, so why not?

- Ignite
This is basically one of the best summoner spells in the game, ever. Early on, it lets you snag kills that would otherwise be close getaways, giving your the gold and XP advantage. Late-game, it snags close kills and can counter some healing-reliant champs, like Dr. Mundo. This spell is just amazing; don't underestimate it.

- Cleanse
Jayce does not like CC. He is technically ranged, yes, but a lot of his damage comes from his melee combo, and stuns or even slows can ruin your day. This will get you out of trouble.

Other spells to consider include Heal (early-game sustain + late-game teamfight advantage0, Exhaust (another way to snag those early-game kills), and Ghost (combined with your other abilities, you can cross the map at a blistering speed to give surprisingly quick ganks and get away from almost any bad situation).



BUT WHY NOT FLASH?

Quite simply, because you don't need it. Hextech Capacitor, your passive, gives a burst of speed whenever you use your R (which is on a 6-second cooldown), and Acceleration Gate also gives you some speed. Jayce is quite incredible at getaways and at covering ground quickly, and the combination of To The Skies and the Mercury Cannon mean that he has quite a few ways to catch a fleeing enemy. After using flash on Jayce, I decided that it just didn't make enough of a difference to justify giving up, say, Exhaust.

When it comes to killing creeps, Jayce is awesome. Late-game, he can use Acceleration Gate + Shock Blast to instakill(!) huge swarms of creeps, or dish out major damage with To The Skies and Lightning Field. Plus, you'll have plenty of targets to hit with your hammer who can't fight back very well, so your mana needs are taken care of.

Once you have lifesteal and tons of health, you can basically turn neutral creep camps into mana wells. Run in with your hammer, bash them to death, and look! Your mana has magically reappeared!