Modeling boards

Use Space zones when board membership, position, face-up state, and named areas are canonical. Use a token map when concurrent occupancy must preserve every entity, as Watershed does. Keep a derived grid, score, or index out of the canonical state unless it has a clear rebuild and conflict policy.

Specify bounds, legal moves, collision behavior, deletion/tombstones, and ordering. Concurrent moves can create a contested cell, a multi-value conflict, or a deterministic winner; choose and display one deliberately. A Space placement is not a permission system, and face-down does not guarantee secrecy from peers who received the document.

Use a server authority for referee decisions, rate limits, and moderation. A peer mesh is a good fit for offline maps and collaborative territory; it is a poor fit for competitive boards where an untrusted client must not author the outcome.