6.1. Eligible grades: II–XII; Grade XII students compete in the Final under Category XI.
6.2. Participation is possible only through the Official Partner; the selection of the partner and the formation of the team are conducted domestically under transparent rules.
6.3. Normally, 1 team from each country is admitted; for the host country, the possibility of a second team is subject to the decision of the EIB (specified in the Annual Rules).

 7.1. Official languages: English, Russian, German.
7.2. The country partner may also hold the exam in its national language; the country partner is responsible for the accuracy of the translation and equivalence of the content.

Materials
8.1. Duration: 90 minutes; number of questions: 25; format: multiple-choice.
8.2. Permitted materials: black/blue pen, eraser, transparent ruler.
8.3. Prohibited materials: calculator, smart watch/phone, electronic devices, personal notes/notebook.

 9.1. Scoring formula: Correct +4, Incorrect –1, Blank 0; maximum 100 points.
9.2. Qualification thresholds for the Final: 91–100 Gold, 75–90 Silver, 50–74 Bronze, 40–49 Honorable Mention (all qualify for the Final); 1–39 Participation (no qualification).
9.3. Team results are not calculated in the Selection Round.

 9.4.1. In the Selection Round, awards are given for Gold (91–100), Silver (75–90), Bronze (50–74), and Honorable Mention (40–49).
9.4.2. These awards are accompanied by the right to qualification for the Final (Article 9.2).
9.4.3. Certificates are provided in digital form; the awarding of physical medals/plaques is at the discretion of the country partner and announced in the Annual Rules/national announcements.
9.4.4. Countries may present locally sponsored gifts; however, this does not alter official results or qualification rules.

 10.1. Within 3 hours after the end of the exam, complaints regarding text/printing/ambiguity are submitted by the country leader through the official form.
10.2. Decisions may be applied as a unified announcement to all exam halls.
10.3. This window does not replace the Moderation procedure (Section 4).

 10.4.1. Appeals regarding the Selection Round begin after the announcement of exam results (not immediately after the exam).
10.4.2. Appeals may only be submitted by the country representative/country leader via the official form.
10.4.3. The aim is to ensure fairness: substantiated technical/content-related issues are reviewed; if necessary, the matter is referred to the Organizing Committee (OC).
10.4.4. Implemented decisions (score change, neutralization, etc.) are formalized with an official protocol and applied uniformly to all halls/countries.

11.1. In online mode, a single-tab/single-window policy is applied; remote proctoring and audit logs are implemented.
11.2. Participants may only use the official platform and permitted resources.

 12.1. Students who have qualified from the Selection Round participate in the Final.
12.2. Results are calculated individually and by team; the team result is the total sum of the final scores of all finalists from the same country.

 13.1. Official languages: English, Russian, German.
13.2. Official translation into the national language is possible and subject to an additional fee (mechanism specified in the Annual Rules).
13.3. Evaluation is always based on the English version

 14.1. Duration: 120 minutes; number of questions: 25.
14.2. Format: mainly multiple-choice; if necessary, open-ended/analytical questions may be added.
14.3. Official notification on the inclusion of open-ended questions is published at least 30 days before the exam.

 15.1. Entry to the hall is possible only with ID and accreditation badge; lateness limit: 15 minutes.
15.2. Exit from the hall is permitted only with the supervisor’s authorization; sanitary breaks must be accompanied.
15.3. Prohibited equipment: calculator, smart watch/phone, electronic devices, personal notes/notebook.
15.4. IB/EB members are prohibited from entering the exam halls during the exam; only supervisors, security staff and medical personnel (in case of necessity) may be present.
15.5. Task sets are distributed in sealed containers; unused materials are collected after the exam and securely destroyed.

 16.1. For the purpose of ensuring transparency of the exam process, video monitoring is conducted in the halls; live broadcast may be provided on official channels with general views and overall process images.
16.2. To protect personal data, close-up faces, answer sheets and individual information are not shown; audio broadcasting may be limited or turned off.
16.3. Recordings are archived; storage period and access procedure are specified in the Annual Rules.
16.4. Parental/guardian consent may be required; media usage terms are regulated in accordance with Section 1 and the Annual Rules.

17.1. In the Final, the scoring formula is: +4 / –1 / 0; maximum 100.
17.2. If there are open-ended questions, rubric-based evaluation is applied; partial credit is awarded only according to the rubric.
17.3. The scoring process is supervised by the Jury.

18.1. After grading is completed, leaders are provided with participants’ scores, answers, and a summary of feedback.
18.2. Documented decisions regarding rule violations are communicated to the parties.

 19.1. If a tie occurs in the Final affecting World 1st, 2nd, or 3rd places, a mandatory Tiebreak Exam is conducted (short, new questions).
19.2. The Tiebreak result takes precedence; in case of a complete tie, the order is: time → age → Jury decision.
19.3. For ties affecting medal thresholds but not the top-3, Article 19.2 applies accordingly.

 20.1. At both stages, within 3 hours immediately after the exam, an initial complaint may be submitted regarding issues in text/printing/ambiguity (only by the country leader, via the official form).
20.2. Moderation (Final) begins after the official results are announced and lasts 4 hours; 1 representative per country, in the format of a 10-minute presentation + Q&A.
20.3. If a question/key is erroneous, the decision is applied in favor of all participants; otherwise, results remain unchanged.
20.4. Appeals regarding open-ended questions must be submitted with rubric-based justification.
20.5. Jury decisions are final.

 21.1. Medal distribution (relative): Top 8% — Gold, next 15% — Silver, next 30% — Bronze, up to the next 50% — Honorable Mention.
21.2. Special awards: World Champion, 2nd place, 3rd place by grade, Best Student by country, etc.
21.3. All participants and leaders receive a Certificate of Participation.
21.4. The rules for publication of tasks and official keys are specified in the Annual Rules.

 21.5.1. Participants in Grades 11–12 who achieve high results in the Final may be considered for admission by selected universities.
21.5.2. Scholarships may be offered by respective universities (e.g., 100% / 75% / 50% / 25%).
21.5.3. Admission and scholarship conditions, quotas, and criteria are regulated by the universities’ own rules and announced separately through official channels.

 22.1. Cases of plagiarism, cheating, third-party assistance, use of prohibited devices — subject to sanctions including disqualification.
22.2. In cases of Conflict of Interest (COI), the respective persons may not participate in supervision or evaluation concerning their own country/students.

 23.1. The Selection Round is fee-based; the amount is determined by the country partner and announced through official channels.
23.2. Payment channels and deadlines are specified separately for each country.

 24.1. The Final is fee-based; tariffs are announced in advance by the Organizer.
24.2. Sample packages (approved in the Annual Rules): Exam, exam + cultural.
24.3. In the Final, official translation into the national language is subject to an additional fee.

 25.1. Refund matrix: Until 05.08.2026: 80% · Until 25.08.2026: 50% · Until 01.09.2026: 25%. During the last 30 days and no-show: no refund.
25.2. Force majeure requests are evaluated on a case-by-case basis.
25.3. The mechanism of payment receipt/confirmation and rules for official receipts/proformas are specified in the Annual Rules.

 26.1. Eligible applicants: public/private educational institutions, NGOs, associations, and other legal entities.
26.2. Stages: Preliminary (by January 31), Early-bird (by February 1), Late (as per Annual Rules; usually ≥1 month before the Final).
26.3. Acceptance/rejection decisions are made by the EIB based on criteria; additional information may be requested if necessary.

 27.1. After at least 1 year of participation, application for a 3-year agreement is possible.
27.2. Once approved: exclusive Official Partner status in the country and the right to use the ESO logo/brand elements in national competitions are granted.
27.3. During the 3-year agreement, no other applications from the same country are accepted.

 28.1. To conduct the national selection and present an annual roadmap.
28.2. To comply with data protection, ethical rules, and COI (Conflict of Interest) policy.
28.3. To submit quarterly short reports and adhere to official communication requirements.

 29.1. Logo/brand usage is permitted only with written authorization; usage rules follow the brand-book.
29.2. In cases of breach of terms, falsification, ethical misconduct, or inactivity, the EIB may decide on suspension/termination.

 30.1. The Organizing Committee (OC) has the right to make changes in dates, format, procedures, and technical requirements in cases of necessity or force majeure.
30.2. Changes are announced in advance through official channels and are applied only prospectively.
30.3. In case of conflict with the Annual Rules, the Annual Rules prevail.

 31.1. Technical matters related to exam content and scoring are regulated under Section 4 (Moderation and Complaints).
31.2. Administrative complaints concerning management/service issues are submitted in writing to the OC.
31.3. Mediation and alternative dispute resolution mechanisms may be applied with the consent of the parties.
31.4. The official interpretation of the Rules and the authority of final decision belong to the ESO International Board (ESOIB).
31.5. Jurisdiction and applicable law are specified in the Annual Rules.

 32.1. Tasks, keys, rubrics, protocols, and other materials are protected by copyright; unauthorized reproduction and distribution are prohibited.
32.2. Use of the ESO name, logo, and brand elements is allowed only with written authorization and in accordance with the brand-book rules.
32.3. Official partners must comply with transparency and quality standards in brand usage.

 33.1. All staff and partners must comply with child protection policies; background checks may be applied if necessary.
33.2. An anonymous channel is provided for complaints and reports; in urgent cases cooperation with law enforcement and social services is ensured.
33.3. Use of media and images is permitted only with the consent of the relevant parent/guardian.

 34.1. Official invitation letters are issued by Germany; a Schengen visa is required for most countries (estimated processing time 10–15 business days).
34.2. For official participants, airport–hotel–venue transfers are provided in accordance with the Annual Rules; official hotels are mainly 3–4★ category.
34.3. Security and medical support are provided 24/7 during the competition.
34.4. Contingency plan (online/hybrid): implemented on a secure platform, with single-tab/single-window policy, remote proctoring, identity verification and audit logs.

35.1. Personal data are processed for purposes of registration, accreditation, certification, and statistics.
35.2. Retention: exam papers/scans for 12 months, final protocols and certificate registries for 5 years.
35.3. Photo/video usage only with proper consent; close-up images of faces and answer sheets are not shown in public broadcasts.
35.4. Data transfer and disclosure are carried out in accordance with applicable legislation.

36.1. Applications for physical accessibility, seating, extra time, etc. must be submitted with medical justification by September 1.
36.2. Adjustments are implemented provided that the integrity and security of the exam are not compromised.
36.3. Decisions are confirmed in writing and communicated to the relevant staff.

37.1. This article is applied together with and complements Section 4, Article 22.
37.2. In cases of COI, authors, markers, translators, and supervisors may not supervise or evaluate participants from their own school/country.
37.3. Sanctions for violations: warning, score nullification, disqualification from the stage or competition.
37.4. All sanctions are documented and communicated to the parties; decisions are final.