This paper presents the design and implementation of a web-based platform for three-player chess, a non-standard variant developed by Dario Varga that until now has only existed in physical form. The work addresses several human–computer interaction challenges: intuitive visualization of a hexagonal chessboard, synchronization of three players in real time, and support for learning unfamiliar rules. The platform was developed using Node.js, React, Mantine, Socket.IO, and MongoDB, providing user account management, both single-device and online multiplayer modes, and access to game history. A key contribution lies in creating a user-friendly and responsive interface that lowers the entry barrier for new players while ensuring robust performance in real-time gameplay. Evaluation conirmed that the application meets functional requirements and ofers minimal latency for online play, with results highlighting the impact of server proximity on player experience. The project demonstrates how thoughtful interaction design and modern web technologies can support the digital transformation of analog games, broadening accessibility and engagement with alternative chess variants. The system is available at:
https://chess3.musiclab.si/
