Sandbox — contest that lasts the whole period of CodeBall 2018 championship. Sandbox opens December 16, 2018 at 21:00 UTC and closes February 10, 2019 at 21:00 UTC, which is a week after the Finals.
To participate in the championship, you need to have at least one accepted strategy in the Sandbox at the moment Round 1 starts. You can submit your strategies to the Sandbox any time and create games with it. Qualification games are regularly created in the Sandbox. In a qualification game only your last submitted (and accepted by the system) strategy takes part. Participants of a qualification game are chosen randomly. Each strategy takes part in about one qualification game per hour (this interval may be changed by the jury, but is the same for all the participants). Rating of the participants is calculated based on results of these games. The starting rating value of 1200 is assigned to anyone, who submitted a strategy (and it is accepted by the system) to the Sandbox.
A modified version of the Elo rating system is used for rating calculation. In short: an expected place is calculated for each participant, and his rating increases in case of him taking a higher place, and decreases in case of taking a lower place.
1080 participants with the greatest rating in the Sandbox are chosen to participate in Round 1 (in case of equal ratings a participant who submitted his strategy earlier has bigger priority) at the moment of Round 1 beginning.
In addition to qualification games, participants can create their own games. To do so, you need to submit your strategy and choose opponents. You can choose any strategy submitted not later than your last accepted strategy as an opponent. You can select any version of your strategy available at the moment of creating a game. When you create a game, you can choose one of no more than three formats: 2x2, 2x2 with nitro or 2x3 with nitro. Before Round 1 only 2x2 type of games is available, before Round 2 only 2x2 and 2x2 with nitro game types are available. After Round 2 all 3 game types are available.
Results of games created by participants do not affect final results. Qualification games will be held until the end of the championship. These games affect only ratings of the participants in the Sandbox and will not be taken into consideration in the championship itself. Although, before each stage of the championship (except for Round 1) best strategies from the Sandbox will be allowed to take part in the championship. So, 60 strategies with the greatest rating in the Sandbox, that did not pass to Round 2 in the main championship will be allowed to participate in Round 2. Similarly, 10 additional strategies will be allowed to participate in the Finals. After the Sandbox closes on February 2 at 21:00 UTC, authors of the best strategies will be given prizes (Finals winners will be not included in this list).
Participants who have been eliminated from the championship can still improve and submit their strategies, as well as create their own games. They are still rightful participants of the Sandbox, and in case of high results also compete for special prizes.