Product
Kai-Dom Engine
keye-DOM
The verdict of the turn.
回 Kai — Japanese, “turn, rotation”+ᛞᚢᛗᛦ Dómr — Old Norse, “judgment, verdict”
A real-time match and rotation state machine for volleyball officiating and scorekeeping — legal rotations, substitutions, and scoring enforced by state, not memory. Built for the sideline, not the scorebook.
6-player court rotation modeled as a cyclic permutation, with slot-lock and libero-boundary invariants enforced by the state machine itself, not a human double-checking a lineup card mid-rally.
What’s inside
Match integrity
6-player court rotation as a cyclic permutation — the engine, not a coach's memory, enforces legal order
Slot-lock and libero-boundary invariants: illegal states (e.g. libero rotated into the front row) are rejected, not silently allowed
Substitution quota enforced per ruleset — 12 standard, 15 NCAA
Auditability
Every rally logged as a hash-chained token (SHA-256 prevHash/entryHash) — identical scheme to SpeedStack's own FSM core
Log-first discipline: the record is written before the state change is considered final
Built on top, not bolted on
vball-8bit renders the engine's real match state directly — no separate copy of the rules to keep in sync
Mei-Vald Index consumes this engine's own rally log as its only input, no separate data pipeline