For season 6.

UPDATE: Jarvan got a decent buff to his shield and his ult. His shield will now make him tankier and his ult now does damage to everyone in his cataclysm rather than just the person in the middle. This directly buffed his survivability after engaging, which has made him stronger at all points of the game.

You can either go 12/0/18 or 12/18/0, but I have found the 12/0/18 mastery tree to be more successful. I like to take Strength of the Ages because it gives some decent stats as you farm up the jungle. Having 300 hp is like buying 2 ruby crystals, which makes it a keystone worth 800 gold. If you were to go the 12/18/0 tree, you are going to be more of an offensive threat and you would go Thunderlord's Decree .

Start With:

Hunter's Machete is a MUST. Trinket ward is a MUST. Some junglers like to go with Refillable Potion over the 3 potions. It IS more cost efficient however if you start with 3 pots, you will be healthy enough for a gank after your first clear. See jungling section.*

First Back/Early Game:

Self explanatory. Against burst champions, you'd want to take Skirmisher's Sabre because it reduces damage done to you by 20%. Let's say there is a Zed/ Brand, you can gank with smite up and be confident that you can out-damage that mid laner. If it is someone like Akali/ Ahri, you can "counter" their mobility by using Stalker's Blade and smiting them when they try to run away/out-maneuver you.

Once you get your jungle item, you want to rush Warrior Enchantment for that 60 damage and 10% CDR. After you get that, try to invest in some boots before any other item to ensure you can rotate to objectives and get into fights fast enough.

Mid Game:

If you are really ahead, GO MAN MODE! Get Tiamat and start dominating your territory! Build this into a Ravenous Hydra if you already have a tank, build into a Titanic Hydra if your team needs more tank. If not ahead and not behind, standard build would be to get a Phage. Good tankiness with the 200 health and nice damage with the 15 AD. Build this into a Black Cleaver. If going against a heavy AP damage, Hexdrinker is a smart buy which not only gives you mr, but also a shield that helps survive some skirmishes.

If behind, FORGET THE DAMAGE!!! Seriously, I see WAY to many players trying to go damage when they are behind. There is NO point in going damage if you can't survive long enough to deal it! This alone makes you better than the average LoL player. Know how to play behind, your team's needs are more important than you. You can go 0/5/0 and still carry by being the tank and peeling for your carries! I sometimes like to even pick up a Sightstone if more vision is needed. It gives a decent 150 health for tankiness and 3 wards which I think is worth the buy.

Boots:

This section is self explanatory. I believe most players understand the concept of going Ninja Tabi when a team is AD heavy and Mercury's Treads when they are going against AP/cc heavy teams.

Situational Tank:

As of right now, Dead Man's Plate is one of the strongest items for juggernaut junglers because it gives you movement speed, tankiness, and damage! Must buy item imo. If the adc or a champion who is basing their damage off of crit is fed, Randuin's Omen is an amazing item. Its 60 armor, 450 health, passive and active make it easier for you to not get kited easily. Both are very strong for junglers. If the enemy team has some decent AP damage the health on each helps you take some more damage. How I decide which one I'm going to get is by asking myself if the enemy team is more auto attack based or not. Randuins slows auto attacks and reduces crit strikes while deadman's plate does not.

If there isn't much AP damage and/or the enemy team tends to rely on auto attacks for damage, Frozen Heart is the way to go! I personally like to buy Randuin's or Dead Man's but sometimes the armor is absolutely needed to counter a fed adc. The extra mana and cdr make Frozen Heart a really good alternative. As for Thornmail, it should really only be picked up when you're going against heavy AD damage but should not be bought before getting some health.

Banshee's Veil should be used against high/bursty AP damage and cc. Locket of the Iron Solari is more for AoE damage as well as help against AP damage (This is usually picked up by the support and does not stack, so make sure to communicate to the team that you are going locket).

It is very difficult to draw out one specific jungle start/route that will work 100% of the time however there are routes that can help optimize your play. I generally like to start bot side first for the better leash. I usually start at krugs / gromp by E + smiting it immediately and wacking it until it dies while my pot keeps me healthy enough to go to my blue/red buff. I do this to increase my attack speed while stunning/poisoning the camp. If you are worried about an invade, saving the smite to last hit the camp is better. Next I E + Q the blue/red buff and continue to wack it around. Always try to position yourself so that you are hitting all minions in the camp. Next you must make a decision: choose to go directly to your next buff and look for a gank or start your wolves/raptors and then either back or start your next buff. If you are going against an aggressive jungler who might counter-jungle you at your next buff, backing after your first camps is okay. I personally think the sustain from the 3 pots and smite should be fine to do first camp + buff + buff + gank, but that is because I am comfortable with the jungle clear and my ability to disengage with my E + Q.

If you do choose the gank path and there are no opportunities available, take the scuttle crab on top side. It gives decent gold, lifesteal will make you healthier, experience is good, vision and speed boost is very useful. If there still is no opportunity for a gank, just back and buy your first item, Stalker's Blade or Skirmisher's Sabre.

The Pre-Gank:

Constantly check which opposing lanes are showing aggression and are overextended. These are the lanes you want to gank because the enemy needs to cover more distance to get back to safety. The other important aspect to pay attention to is ward placement. It is the team's job to let you know where wards might be in their lane. Over time, you will get a feeling as to where laners typically like to ward. For a gank to be successful, you must AVOID BEING SEEN AT ALL COSTS!! If the laner SEES you, they will know what is going on and will either back off or bait you into a bad fight. I cannot emphasize enough how CRUCIAL this is to ganking. You should also PING where you are going so that the laner knows you are ganking. This is not exactly your job but it does make it easier for the laner to follow up on a gank. Typing what you are trying to do can also help out at times. Finally, you must know what spells are on cooldown, FOR YOUR TEAM AND THE ENEMY TEAM (especially ults and summoner spells). If you gank for your Wukong top and he has all his moves on cooldown, even though the enemy might have nothing, that Wukong won't be able to come into the fight, close any gaps, cc, or do any serious damage since his cc and most of his damage comes from his spells.

The Gank:

As Jarvan IV you have one of the strongest ganks in the game. Your E-Q combo is your bread and butter, and you HAVE to be confident in yourself. The hardest part about ganking is the communication between the laner and jungler on how to make the gank successful. Generally speaking, there are two ways to gank with Jarvan IV.

First one is to land that E-Q knockup to have you and your laner whack the opponent to death. This is by far the hardest because it requires the most information from your lane. Does the enemy have an escape/dash? Does he/she have flash ready? Does YOUR laner have any form of crowd control? I'll try to be short and concise. If the enemy has a dash, walk up to them and bait it out BEFORE you use E + Q. A lot of players will try to predict your E + Q and dash BEFORE you even use it, and BAM, you get an easier E + Q. Sometimes the opponent is too far and you have to try to E + Q them before they get away and this is when YOU have to predict their dash and E + Q in a location where you think they will go. There's good news and bad news. The bad news is that if you predict wrong, you might not get anything from the gank. The good news is Jarvan IV's E + Q combo is more of a wall of cc rather than a point so it's actually a lot easier than you think AND even if you miss, your E + Q can be used as a zone tool and your laner can use that to catch up to the enemy. For example, let's say you were trying to catch a Graves who still has his dash up: If you were walk up to him at a diagonal and E + Q behind him, you will basically build this wall that he cannot pass or else he will be knocked up. If he decides to dodge and move closer to you he will only have so many other places to go and your bot lane will be able to take care of that. Remember, even if you DON'T catch him, it leaves only so many other places he can go to escape damage/cc. Learning how to not be afraid to engage with this combo is very important and you have to trust that you made the right decision.

The second way to gank is to use your E + Q as a gap closer and then using ULT on the enemy. The range on this combo is ridiculous and it is VERY fast considering the distance traveled. This combo is usually only done when you KNOW the person can't dash/escape the walls of your ult. I personally like to go to bot lane through lane, stand in the bush closest to tower and use this combo to completely trap the enemy ADC + SUPPORT.

After The Gank:

After a successful gank (laner dies or recalls to base), you always want to try to push the wave to the enemy tower to deny the enemy some cs. If the lane is pushed towards YOUR tower, it's up to the laner if he wants it pushed or not. However if the lane is already pushed a bit, push it all the way and if your laner wants to yell at you for taking cs and making them "fall behind" don't listen to them! Push it to tower because it will help your TEAM more at the end. You will be DENYING them cs, while giving your team MORE cs and some exp. Remember, it's a team game!

If the laner does NOT leave lane and you got a flash out, all is not lost! This is actually very good because now the enemy laner has to play more careful and will therefore respect your presence. This means the enemy will try their best to NOT overextend and possibly give up some cs. Your laner will have the advantage and everyone is happy. After this gank, you should ask yourself three things:

1) Am I healthy enough for another gank? (if yes go to 2, if no look at 3)
2) Are there any other lanes that are overextended? (if yes GO GANK!, if no go to 3)
3) Do I have smite up for another camp? (if yes do another camp, if no recall and buy)

Whether you chose to recall and buy, or do another camp, you should constantly check for aggression for THAT SAME LANE. That is one less escape that the laner has for 5 minutes. That is 5 minutes of free kills for your team. It is also a target lane for the enemy jungler because they will want to be there, that is why you must make sure you are ready for a possible 2v2.

After understanding basic knowledge of the game, the next step is to work on your decision making in game. One of the BIGGEST issues I see in lower elo (Bronze/Silver/Gold) is the poor and/or lack of decision making done when opportunities arrive on the map. Many times I see a jungler start a camp and insist on finishing it before joining a fight and/or objectives. THIS IS A BIG MISTAKE! Please, please, PLEASE, do not be one of these junglers. I cannot tell you how many times a double kill for the enemy team could have turned into a triple kill for my team, had the jungler left the camp immediately and helped with the fight. I understand that the jungler has to farm but if you start [krugs] and kill one of the two, and a fight starts in the nearest lane, forget the second krug, IMMEDIATELY go to that lane and enter the fight. This is why: Chances are, the enemy does NOT know you are there, or else they wouldn't have started the fight! This means that you have the element of surprise and will most likely deal out free damage. The enemy has probably used up important spells in the fight and have no cc or damage to handle you entering the fight. It's plain and simple, 2 is better than 1 and 3 is better than 2.

The next step in becoming a better jungler is knowing how to react when you are given certain information. Too many times I see junglers do nothing when their top lane gets ganked by the enemy jungler. They think "Well I'm bot side so I can't do anything about that." This is false! Instead of looking it as, "Oh well he's dead", think of it as "Jungler is top! What can we get out of it?" Let's put ourselves in a situation. Top side gets ganked by a jungle Malphite that ults in. You are bot side jungle and see this. What do you do? Well, you can gank mid or bot and get tower and/or dragon! You can go into malphite's jungle and take some of his stuff (maybe even his blue/red in some cases). You have to know how to take advantage of information! If you cannot learn to do this, you cannot consistently win games for your team because you will be missing out on a lot of objectives. You can literally win losing games if you learn how to do this. TRUST me.

Another important aspect to jungling is being able to confidently shot call. This is probably the hardest one of them all because it will only come with experience. My advice to you would be to make aggressive shot calls and see what happens. Sometimes we are going to make mistakes, it's inevitable, so don't let the fear of losing get in the way of progress. I can't count how many times I called baron and lost the game. This will happen, but over time you will realize when a call is good and when it is bad.

Lastly, be confident. You are the jungler. You decide what objectives you get. Act like it. You cannot carry games if you are not confident in your ability to do so. A good attitude projects better gameplay! So play on friend :)

This guide is not yet finished but if you have any questions, comments, or suggestions feel free to leave a comment in the guide discussion! I hope this guide helps anybody who is trying to become a new/better jungler as Jarvan IV and in general!