1. The principle of competition is the core of bidding activities. Without competition, bidding becomes a mere formality; uncontrolled competition leads to collusion, fraud and waste of public resources. This article analyzes the competition principle for contractors under the Law on Bidding No. 22/2023/QH15 (as amended by Law No. 57/2024/QH15 and Law No. 90/2025/QH15 – collectively the “Bidding Law 2023”), and the special provisions under the Law on Railways No. 95/2025/QH15 (the “Railway Law 2025”), together with an evaluation of their practical advantages and disadvantages in Vietnam.