Hello,
This is my short guide to explain how Jarvan IV works in solo top lane.
All the details in this guide are personally MY OPINIONS, but suggesting better item choises for example to the comments are totally welcome!

Martial Cadence This is Jarvan's passive.

Jarvan IV's first attack on a target deals 10% of their current Health as bonus magic damage (max: 400 damage). This effect cannot occur on the same target for 6 seconds.


Dragon Strike

Jarvan IV extends his lance, dealing physical damage and lowering the Armor of all enemies in its path. Additionally, this will pull Jarvan to his Demacian Standard, knocking up enemies in his path.
Jarvan IV extends his lance, dealing 70/120/170/220/270 (+) physical damage and lowering the Armor of all enemies in its path by 10/14/18/22/26% for 3 seconds.

If it contacts his standard it will pull Jarvan IV to its location, knocking up enemies in his path.

Cost: 40/45/50/55/60 Mana
Range: 770

Your main harassment spell, the so called "bread and butter". Does nice amounts of physical damage and totally rapes the squishies off! Watch out to use it too frequently in case you need to escape or interrupt a spell with it.




Golden Aegis

Jarvan IV calls upon the ancient kings of Demacia to shield him from harm and slow surrounding enemies.
Jarvan IV forges a 50/100/150/200/250 (+20/25/30/35/40 health for each nearby enemy champion) health shield for 5 seconds, which slows surrounding enemies by 15/20/25/30/35% for 2 seconds.

Cost: 75/75/75/75/75 Mana
Range: 600

This ability can be used either offensively or defensively and synergies very well with RanduinsOmensize=20 Randuin's Omen.



Demacian Standard

Jarvan IV carries the pride of Demacia, passively granting him bonus attack speed and armor. Activating Demacian Standard allows Jarvan IV to place a Demacian flag, granting these benefits to nearby allies.

Passive: Jarvan IV has 10/14/18/22/26% bonus Attack Speed and 10/14/18/22/26 bonus Armor.

Active: Jarvan IV throws a Demacian flag to a nearby area, dealing 60/110/160/210/260 (+0.8) magic damage to enemies, and granting surrounding allied champions his passive bonus for 8 seconds.

Cost: 60/60/60/60/60 Mana
Range: 830


Cataclysm

Jarvan IV heroically leaps into battle with such force that he terraforms the surrounding area to create an arena around them.
Jarvan IV heroically leaps at an enemy champion, dealing 200/350/500 (+) physical damage and creating an arena of impassable terrain around them for 3.5 seconds.

Activate again to collapse the wall.

Cost: 100/125/150 Mana
Range: 650

Look out with champions that have flash or abillities that can flash!

Ghost and teleport. Standard choice for solo top.

you could also choose:
Exhaust
Flash
Ignite

Other spells i don't prefer

Doran's Shield
Gives you fine amounts Health, Armor and Health Regeneration for early-game.

After your first recall, you should have at least money to gain Heart of Gold, However if you cannot afford it, just take Boots of Speed and a few Health potions. Buying a sight ward Sight ward should be smart because of ganks.

Second recall is starting to tell you how well you have managed to last hit the enemy minions and/or have you possibly also gain any kills? If the answer is positive and you got some good amounts of money it is time to buy boots ofspeed if you don't have them yet and The Brutalizer, if you can't afford it just buy 1 or 2 Long Sword.


Time for the shoes! You have ether 2 options: mercurys tread Mercury's Treads or Ninja Tabi It depends on your enemies so you could choose for yourself!

After you upgraded your shoes its time to upgrade your other items! So we take the brutalizer and upgrade it to Youmuus Ghostblade you can do it in steps if you dont have the money, so u can buy Avarice Blade first. Then we take ur Heart of Gold an upgrade it to Randuin's Omen, u can also do this in steps cause it is an expensive item so first buy an wardens mail Wardens mail and then upgrade it!

Oke that where the core items! Now the build start to depends on your enemies, just look at the classes that are feeded the most.

Caster:

Damage: you should't buy a Hexdrinker a Banshee's veil and a

Tank: Now you buy: Quicksilver Sash, a Banshee's veil and a force of natur Force of nature.

PHYSICAL DPS:

Damage: buy a Frozen Mallet, atmas impaler Atma's Impaler and a Sunfire Cape.

Tank: buy a Sunfire Cape, Thornmail and a Guardian Angel.

Mixed if the enemies got something of all bu this: a Hexdrinker, banshees veil Banshee's veil and a Guardian Angel.

Support Now if your team needs a bit of support buy this: Aegis of the Legion, Frozen Mallet and a Stark's Fervor.

We came to the end of my short guide! I know its really short but who cares if its short, as it works! But if u got any tips to make this more powerfull reply pls!

Hope you all have much fun with this!
Goodluck, slaying your enemies!
Meet you on the battlefield

blitz