The paper examines judicial practice regarding the implementation of the adversarial principle in arbitration proceedings. The study identifies stages in the development of adversarial proceedings, driven by the dynamics of socio-economic relations, the convergence of legal systems, the search for approaches and methods to enhance judicial efficiency, and shifts in procedural paradigms. It is established that, as a result of judicial application, rules of adversarial proceedings have been formed based on facilitating justice, the good-faith disclosure of truthful information, and the presentation of evidence relevant to the case. Courts have defined exceptions to the general rule of burden of proof distribution — inequality in procedural opportunities for proving and bad-faith procedural conduct, including the withholding of information, failure to present evidence, or refusal to provide explanations. The burden of proof no longer follows unconditionally the burden of assertion: in conditions of inequality of procedural powers of proof, the burden of proof is placed on the party that has or should have the evidence. Such approaches are justified and align with the objectives of the proceedings. At the same time, the principle of legal certainty requires integrating these developed rules into the civil procedural framework, as well as their further elaboration and specification.