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What is JDC?

The Jazz Duelist's Challenge is an ongoing Jazz Jackrabbit 2 tournament where people compete through duels. Team games with two or three-player teams are also featured, as well as occasional large games which are known as "events".

You can duel whoever you want as long as they are also signed up with JDC, and you can duel them whenever you want. You can do as many or as few duels as you want. You don't even need to duel at all; many people participate in JDC just for the events which are hosted regularly.

The JDC website also features highly detailed statistics on a lot of things, and is almost entirely automated. Users are expected to submit their own matches to the site and are trusted to be honest with their submissions. The administrators do their best to ensure everything stays that way.

A patch called JJ2+ is used for a lot of JDC events. It would be a very good idea to download it, as some events require it, and others are helped a lot if you have it installed. Get it at Jazz2Online.


Points determine who wins and who loses in JDC. Points can be obtained through events or matches. If you are interested in detailed information on how points are obtained, see the section on scoring.


JDC is organized into a series of seasons. At the beginning of each season everybody has 0 points, and at the end whoever has the most points is the JDC champion. Previous seasons are archived, although accounts are carried over so there is no need to re-register. It is important to log in at the beginning of the season though, so your account is recognized as active.


Each season is divided into a series of week-long rounds. Rounds can be thought of miniature seasons, and each one is worth a certain amount of points towards your overall score for the season. Your score for each round is determined by the matches you play in; events go directly to your "overall" score. Once a round ends its scores become permanent.


A duel is a game played between two people. Duels usually determine the bulk of your score for a round.

A team match is played between 4 or 6 people (with teams of 2 or 3 people each). Team games are scored the same way as duels are scored, but don't give bonus points. See the section on scoring for more info on how duels and team matches are scored.


An event is any game that is not a duel or team match. They are typically hosted by officials or administrators, although exceptions are sometimes made for very small events. Instead of being incorporated into your score for the current round, they are simply worth "raw" points that are added directly to your overall score. Because of this, playing in events is always beneficial, even though they usually aren't worth very much. Events are sometimes planned ahead of time, and sometimes they are completely spontaneous. They can involve any number of players, and can be any gametype.


Administrators are the people who run JDC. Check the user list to see which administrators are currently active. They are not allowed to win the JDC tournament, although they are permitted to participate and gain points.

Officials' offer organisational support and their privileges include posting news, hosting events, the ability to levels to the site, and just helping out in general. Anyone can be an official as long as they are reliable, have a good grasp of English, get along with other players, and are at least semi-dedicated. If you fit these criteria, feel free to contact an administrator. We are always looking for new officials willing to help out. Note that unlike administrators, officials are allowed to win the tournament.

Match rules

A competitor (the challenger) challenges another competitor (the opponent), as a team of up to three people or individually. Here are the ten duel commandments:

  1. If the opponent accepts, then the competitors select the level, game type (battle or CTF), roast/point limit and host.

  2. If the challenger accepts, then the competitors select a time to play, if not immediately. The competitors may agree to have one or the other host, or they may have someone else host their match. It is considered rude to complain of lag during a match. You are supposed to agree on the host before a match, not during one!

  3. When the match is over, one of the participants of the challenging team enters the results into the JDC database using the add match page. All matches require a screenshot of the final score to be uploaded with them.

  4. The other player(s) then need to verify the match. Players that have already verified a game will show a tick next to their name on the verification page. Once at least one player of both teams has verified, the match will be fully verified within 24 hours; or immediately once all players have verified.

  5. Matches must be added IMMEDIATELY after they have concluded. Don't wait and add a bunch of matches together at a later time, it looks like cheating. The administrators WILL delete matches which look in any way suspicious.

  6. You are not allowed to play the same person over and over. If you do a large amount of matches against the same person over a short period of time, expect most of them to be deleted. This rule exists to prevent cheating.

  7. Likewise, you are not allowed to play people who do not play jj2. In other words, do not have your friend who has never heard of the game make a JDC account just because you can get easy points that way.

  8. Please be honest about your scores. We are giving you the privilege to send in your own scores. If this privilege is abused, players can and will be restricted from using the site, and if necessary, banned.

  9. You have the opportunity to write short comments on your matches, and are encouraged to do so. Please keep it civil.

  10. The JDC administration has the right to remove a competitor from the tournament for any reason. Anyone found cheating through trainer programs, by deliberately exploiting glitches, or by submitting false information will be banned: cheating in the tournament is not tolerated.

Rules of Events

  1. Please listen to the host of the event and any other JDC officials present. Running a large event requires everybody's cooperation. Officials have the right to kick anybody they consider to be disruptive.

  2. Please play with whatever name you use for your JDC account. This helps the officials know who you are when it comes to submitting scores. If you play with a weird name, don't be surprised if you don't get any points.

  3. Officials will often talk in colour to make what they have to say stand out. Unless you have something very important to say, please don't talk in colour.

  4. Events which are planned ahead of time usually have pregames that are hosted 15-30 minutes before the event. These pregames are not worth points, and are hosted for organizational purposes. Attending pregames is usually a good idea. Postgames are also hosted occasionally.

  5. To allow as many people to get a chance to play as possible, idling is not permitted. Idle players will often be kicked from events to make room for other people. Those who are kicked are free to rejoin, although they might not receive points if they join mid-game.

  6. For team based events, join as default team unless stated otherwise. If you leave an event or are disconnected/kicked and chose to return, please play as the same team that you were on before. Teams will be random in most large events.

  7. Do not complain of lag or anything else. If the event does not suit your tastes, leave. The hosts put a lot of time and effort into what they do, and do not appreciate it when they are ridiculed.

  8. Many players enjoy doing small events such as 4 vs 4 or 5 vs 5 ctf games. This is fine, but doing them in excess is considered unfair. Because of this, you are only allowed to get points for one of these a day. You can play in more, but you will not get any extra points.

  9. Some of the larger events are hosted more than once so more players can get a chance to play. The separate hostings are usually done on different days. Sometimes they will also be hosted at different times of day to account for time zones, although this doesn't have to be the case. For events like this, you may only receive points for one of them. This means if you play in a saturday event, you may not get points in the repeated event on sunday, or any other event identical to it. Sometimes you will be allowed to play in both, but you will only get points for the first one, and you may be asked to leave so others can join if the server fills up.

  10. Events are supposed to be for fun. Do not make a big deal out of things if you don't get as many points as you wanted, because by doing that you will get even fewer points.

Events are hosted with JJ2+, so you need to get it as well. You can get it here.


This section will explain how the scoring system works in simple terms. See the section on "Scoring Equations" at the bottom of this page for specific information.


Your score for each round is a combination of match points (which you get for duels or team matches), bonus points (which you get for playing duels) and event points (which you get for participating in events).


You mainly gain points by playing matches. There is a base amount of points you get per match; this varies from round to round. The base amount of points you will receive is listed in the sidebar on the left side of the site.

These points are adjusted based on whether you won or lost, your score in the match and whether your opponent was better or worse than you (see the section on quality for an explanation of how this is calculated). In essence, the better your score within the match, the more points you gain. So winning with a perfect score (e.g. 5-0) against a strong opponent nets you the most points. Usually losing a match will make you lose points, but even if you lose you may gain some points if the match was close or the opponent was a lot stronger than you.

Each round has a 'match point target', an amount of match points after which the amount of points you can get each match diminishes. This is to discourage grinding your way to the top. You will receive a notification when you reach this target; it's also listed in the sidebar.


At the start of each round, all players receive a bonus pool. This is a number of points that can be gained simply by playing a duel against someone you have not played before in that round. It does not matter if you win or lose!

Once the bonus pool is depleted, it stays empty until the next round starts, and you will only be able to increase your score through match and event points.

The base amount of bonus points you receive per match can be seen in the sidebar. If you play against someone whose player quality (see the next section) is higher than you, you will gain more bonus points (up to twice as many), depleting your bonus pool faster.


To encourage competitors to play against more skilled players, a system called "player quality" exists. Everyone starts at 50% "player quality". After a participating in one full round with a total of 4 accumulated games, you will have a player quality rating in the form of a percentage, based on how often you win. If you win all your games, your quality will be 100%, and if you lose all your games, your quality will be 0%. Note that "player quality" is calculated only from your stats in previous rounds: the current round is not counted.

Player quality is tracked separately for duels and team games.


You can also gain points by playing in events. The next section has more detail on those.

Scoring For Events

Events are generally "weighted" to a certain score. If an event is worth 25 points on JDC, then whoever did best in the event gets 25 points. Therefore, the score people get in-game is almost always different (though proportional) to the actual points they receive.

The actual point value of events depends on how many people play in it and whether the event was announced ahead of time. Larger events will be worth more points, as well as events that have been announced at least 24 hours in advance. Sometimes, the events that mark the end of a round will be worth even more. Here are some general guidelines used for this season.

Any user-organized event with 8 or fewer players is worth 5 points. These events are officially considered "small events", and you can only recieve points for one per day. This limit ONLY applies to "small events".

Events that are organized by officials and not posted ahead of time are usually called "spontaneous events". User-organized events that have more than 8 players are also considered "spontaneous events". These are usually considered a seperate category from "small events". They are usually worth 10 to 20 points, but may be worth more if they are exceptionally large.

Events that have been posted ahead of time will be worth anywhere from 20 to 50 points, depending on factors such as the amount of players and length. 50 point events will generally be the ones that mark the end of the round. Events hosted in the middle of the round will be worth a bit less, in the 30-40 range for a full server. Events that mark the end of the season will be worth the most of all, possibly even exceeding 50 points.

Ultimately, the official who is in charge of scoring the event gets to decide how many points it is worth. They are allowed to use their discretion when it comes to this, so long as the value meets these loose guidelines.

Scoring Equations

If you are interested in the exact specifics of how the scoring system works, this section is for you. Listed below are all of the formulas used in JDC scoring. You don't need to fully understand this, but we provide it anyway in the interests of keeping our system as transparent as possible.

Points are always rounded to the nearest integer number.

Match points

Bonus points

Bonus points are added after the match is verified, using your bonus pool at the time of verification. You only receive bonus points if you have not played the opponent before in that round.

Player quality

Note that player quality is calculated separately for duels and team matches; use the amount of wins and matches for the relevant type.